TOM
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System Approach Using Metabolite Structural Similarity Toward TOM Suggested
A Korean research team at KAIST suggests that a system approach using metabolite structural similarity helps to elucidate the mechanisms of action of traditional oriental medicine.
Traditional oriental medicine (TOM) has been practiced in Asian countries for centuries, and is gaining increasing popularity around the world. Despite its efficacy in various symptoms, TOM has been practiced without precise knowledge of its mechanisms of action. Use of TOM largely comes from empirical knowledge practiced over a long period of time. The fact that some of the compounds found in TOM have led to successful modern drugs such as artemisinin for malaria and taxol (Paclitaxel) for cancer has spurred modernization of TOM.
A research team led by Sang-Yup Lee at KAIST has focused on structural similarities between compounds in TOM and human metabolites to help explain TOM’s mechanisms of action. This systems approach using structural similarities assumes that compounds which are structurally similar to metabolites could affect relevant metabolic pathways and reactions by biosynthesizing structurally similar metabolites.
Structural similarity analysis has helped to identify mechanisms of action of TOM. This is described in a recent study entitled “A systems approach to traditional oriental medicine,” published online in Nature Biotechnology on March 6, 2015. In this study, the research team conducted structural comparisons of all the structurally known compounds in TOM and human metabolites on a large-scale. As a control, structures of all available approved drugs were also compared against human metabolites. This structural analysis provides two important results. First, the identification of metabolites structurally similar to TOM compounds helped to narrow down the candidate target pathways and reactions for the effects from TOM compounds. Second, it suggested that a greater fraction of all the structurally known TOM compounds appeared to be more similar to human metabolites than the approved drugs. This second finding indicates that TOM has a great potential to interact with diverse metabolic pathways with strong efficacy. This finding, in fact, shows that TOM compounds might be advantageous for the multitargeting required to cure complex diseases. “Once we have narrowed down candidate target pathways and reactions using this structural similarity approach, additional in silico tools will be necessary to characterize the mechanisms of action of many TOM compounds at a molecular level,” said Hyun Uk Kim, a research professor at KAIST.
TOM’s multicomponent, multitarget approach wherein multiple components show synergistic effects to treat symptoms is highly distinctive. The researchers investigated previously observed effects recorded since 2000 of a set of TOM compounds with known mechanisms of action. TOM compounds’ synergistic combinations largely consist of a major compound providing the intended efficacy to the target site and supporting compounds which maximize the efficacy of the major compound. In fact, such combination designs appear to mirror the Kun-Shin-Choa-Sa design principle of TOM.
That principle, Kun-Shin-Choa-Sa (君臣佐使 or Jun-Chen-Zuo-Shi in Chinese) literally means “king-minister-assistant-ambassador.” In ancient East Asian medicine, treating human diseases and taking good care of the human body are analogous to the politics of governing a nation. Just as good governance requires that a king be supported by ministers, assistants and/or ambassadors, treating diseases or good care of the body required the combined use of herbal medicines designed based on the concept of Kun-Shin-Choa-Sa. Here, the Kun (king or the major component) indicates the major medicine (or herb) conveying the major drug efficacy, and is supported by three different types of medicines: the Shin (minister or the complementary component) for enhancing and/or complementing the efficacy of the Kun, Choa (assistant or the neutralizing component) for reducing any side effects caused by the Kun and reducing the minor symptoms accompanying major symptom, and Sa (ambassador or the delivery/retaining component) which facilitated the delivery of the Kun to the target site, and retaining the Kun for prolonged availability in the cells.
The synergistic combinations of TOM compounds reported in the literature showed four different types of synergisms: complementary action (similar to Kun-Shin), neutralizing action (similar to Kun-Choa), facilitating action or pharmacokinetic potentiation (both similar to Kun-Choa or Kun-Sa). Additional structural analyses for these compounds with synergism show that they appeared to affect metabolism of amino acids, co-factors and vitamins as major targets.
Professor Sang Yup Lee remarks, “This study lays a foundation for the integration of traditional oriental medicine with modern drug discovery and development. The systems approach taken in this analysis will be used to elucidate mechanisms of action of unknown TOM compounds which will then be subjected to rigorous validation through clinical and in silico experiments.”
Sources: Kim, H.U. et al. “A systems approach to traditional oriental medicine.” Nature Biotechnology. 33: 264-268 (2015).
This work was supported by the Bio-Synergy Research Project (2012M3A9C4048759) of the Ministry of Science, ICT and Future Planning through the National Research Foundation. This work was also supported by the Novo Nordisk Foundation.
The picture below presents the structural similarity analysis of comparing compounds in traditional oriental medicine and those in all available approved drugs against the structures of human metabolites.
2015.03.09 View 9482 -
Professor Joong-Keun Park Receives SeAH Heam Academic Award
Professor Joong-Keun Park of the Department of Materials Science and Engineering at KAIST received an award from SeAH Steel Corp. in recognition of his academic achievements in the field of metallic and materials engineering.
The award was presented at the 2014 Fall Conference of the Korean Institute of Metals and Materials which took place on October 22-24 at the Kangwon Land Convention Hotel.
The award, called “SeAH Heam Academic Award,” is given annually to a scholar who has contributed to the development of new metal and polymer composite materials and its related field in Korea. Following the award ceremony, Professor Park gave a keynote speech on ferrous metals for automotive materials.
2014.11.04 View 7450 -
First Instance of Negative Effects from Terahertz-Range Electromagnetic Waves
Professor Philhan Kim
Electromagnetic waves (EM-wave) in the terahertz range were widely regarded as the “dream wavelength” due to its perceived neutrality. Its application was also wider than X-rays. However, KAIST scientists have discovered negative effects from terahertz EM-waves.
Professor Philhan Kim of KAIST’s Graduate School of Nanoscience and Technology and Dr. Young-wook Jeong of the Korea Atomic Energy Research Institute (KAERI) observed inflammation of animal skin tissue when exposed to terahertz EM-waves.
The results were published in the online edition of Optics Express (May 19, 20104).
Terahertz waves range from 0.1 to 10 terahertz and have a longer wavelength than visible or infrared light. Commonly used to see through objects like the X-ray, it was believed that the low energy of terahertz waves did not inflict any harm on the human body.
Despite being applied for security checks, next-generation wireless communications, and medical imaging technology, little research has been conducted in proving its safety and impact. Conventional research failed to predict the exact impact of terahertz waves on organic tissues as only artificially cultured cells were used.
The research team at KAERI developed a high power terahertz EM-wave generator that can be used on live organisms. A high power generator was necessary in applications such as biosensors and required up to 10 times greater power than currently used telecommunications EM-wave. Simultaneously, a KAIST research team developed a high speed, high resolution video-laser microscope that can distinguish cells within the organism.
The experiment exposed 30 minutes of terahertz EM-wave on genetically modified mice and found six times the normal number of inflammation cells in the skin tissue after six hours. It was the first instance where negative side effects of terahertz EM-wave were observed.
Professor Kim commented that “the research has set a standard for how we can use the terahertz EM-wave safely” and that “we will use this research to analyze and understand the effects of other EM-waves on organisms.”
2014.06.20 View 8795 -
An Exploratory Study on Smartphone Abuse among College Students
Professor Uichin Lee
Professor Uichin Lee of the Department of Knowledge Service Engineering, KAIST, and his research team developed a system that automatically diagnoses the levels of smartphone addiction based on an analysis of smartphone use records.
Professor Lee investigated the usage patterns of 95 smartphone users (college students) by conducting surveys and interviews and collecting logged data. The research team divided participants into “risk” and “non-risk” groups based on a self-reported rating scale to evaluate their abuse of smartphones. As a result, 36 students were categorized as “high risk” and 59 were categorized as “low risk.”
The researchers collected over 50,000 hours of smartphone use encompassing power levels, screen, battery status, application use, internet use, calling, and texting.
The results showed that the “high risk” group used only 1~2 applications, focusing on mobile messengers (Kakotalk, etc.) and SNS (Facebook, etc.).
In addition, a relationship was found between alarm function and addiction levels. Users who set alarms for Kakaotalk messages and SNS comments used smartphones for an additional 38 minutes per day on average.
Results also showed that “high risk” students were on their smartphones for 4 hours and 13 minutes per day, 46 minutes longer than “low risk” students who used smartphones for 3 hours and 27 minutes. The difference was prevalent during 6 am and noon, and 6pm and midnight. In addition, “high risk” students accessed their smartphones 11.4 times more than “low risk” students.
Based on the collected data, Professor Lee developed an automatic system that distinguished users into “high risk” or “low risk” categories with 80% accuracy. The new system is expected to give an early diagnosis of addiction to smartphone users, thereby allowing for early treatment and intervention before the user becomes addicted.
Professor Lee commented that, "the conventional addiction analysis based on self-analysis surveys did not provide real-time data and were largely inaccurate. The new system overcomes these limitations through data science and personal big data analysis" and that he is "developing an application that monitors smartphone abuse."
Figure 1. Usage amount: overall and application-specific results
Figure 2. Usage frequency: overall and application-specific results
Figure 3. Overall diurnal usage time and frequency
2014.06.05 View 7140 -
An Electron Cloud Distribution Observed by the Scanning Seebeck Microscope
All matters are made of small particles, namely atoms. An atom is composed of a heavy nucleus and cloud-like, extremely light electrons.
Korean researchers developed an electron microscopy technique that enables the accurate observation of an electron cloud distribution at room-temperature. The achievement is comparable to the invention of the quantum tunneling microscopy technique developed 33 years ago.
Professor Yong-Hyun Kim of the Graduate School of Nanoscience and Technology at KAIST and Dr. Ho-Gi Yeo of the Korea Research Institute of Standards and Science (KRISS) developed the Scanning Seebeck Microscope (SSM). The SSM renders clear images of atoms, as well as an electron cloud distribution. This was achieved by creating a voltage difference via a temperature gradient.
The development was introduced in the online edition of Physical Review Letters (April 2014), a prestigious journal published by the American Institute of Physics.
The SSM is expected to be economically competitive as it gives high resolution images at an atomic scale even for graphene and semiconductors, both at room temperature. In addition, if the SSM is applied to thermoelectric material research, it will contribute to the development of high-efficiency thermoelectric materials.
Through numerous hypotheses and experiments, scientists now believe that there exists an electron cloud surrounding a nucleus. IBM's Scanning Tunneling Microscope (STM) was the first to observe the electron cloud and has remained as the only technique to this day. The developers of IBM microscope, Dr. Gerd Binnig and Dr. Heinrich Rohrer, were awarded the 1986 Nobel Prize in Physics.
There still remains a downside to the STM technique, however: it required high precision and extreme low temperature and vibration. The application of voltage also affects the electron cloud, resulting in a distorted image.
The KAIST research team adopted a different approach by using the Seebeck effect which refers to the voltage generation due to a temperature gradient between two materials.
The team placed an observation sample (graphene) at room temperature (37~57℃) and detected its voltage generation. This technique made it possible to observe an electron cloud at room temperature.
Furthermore, the research team investigated the theoretical quantum mechanics behind the electron cloud using the observation gained through the Seebeck effect and also obtained by simulation capability to analyze the experimental results.
The research was a joint research project between KAIST Professor Yong-Hyun Kim and KRISS researcher Dr. Ho-Gi Yeo. Eui-Seop Lee, a Ph.D. candidate of KAIST, and KRISS researcher Dr. Sang-Hui Cho also participated. The Ministry of Science, ICT, and Future Planning, the Global Frontier Initiative, and the Disruptive Convergent Technology Development Initiative funded the project in Korea.
Picture 1: Schematic Diagram of the Scanning Seebeck Microscope (SSM)
Picture 2: Electron cloud distribution observed by SSM at room temperature
Picture 3: Professor Yong-Hyun Kim
2014.04.04 View 12975 -
High Resolution 3D Blood Vessel Endoscope System Developed
Professor Wangyeol Oh of KAIST’s Mechanical Engineering Department has succeeded in developing an optical imaging endoscope system that employs an imaging velocity, which is up to 3.5 times faster than the previous systems. Furthermore, he has utilized this endoscope to acquire the world’s first high-resolution 3D images of the insides of in vivo blood vessel.
Professor Oh’s work is Korea’s first development of blood vessel endoscope system, possessing an imaging speed, resolution, imaging quality, and image-capture area. The system can also simultaneously perform a functional imaging, such as polarized imaging, which is advantageous for identifying the vulnerability of the blood vessel walls.
The Endoscopic Optical Coherence Tomography (OCT) System provides the highest resolution that is used to diagnose cardiovascular diseases, represented mainly by myocardial infarction.
However, the previous system was not fast enough to take images inside of the vessels, and therefore it was often impossible to accurately identify and analyze the vessel condition. To achieve an in vivo blood vessel optical imaging in clinical trials, the endoscope needed to be inserted, after which a clear liquid flows instantly, and pictures can be taken in only a few seconds.
The KAIST research team proposed a solution for such problem by developing a high-speed, high-resolution optical tomographic imaging system, a flexible endoscope with a diameter of 0.8 mm, as well as a device that can scan the imaging light within the blood vessels at high speed. Then, these devices were combined to visualize the internal structure of the vessel wall.
Using the developed system, the researchers were able to obtain high-resolution images of about 7 cm blood vessels of a rabbit’s aorta, which is similar size to human’s coronary arteries. The tomography scan took only 5.8 seconds, at a speed of 350 scans per second in all three directions with a resolution of 10~35㎛.
If the images are taken every 200 ㎛, like the currently available commercial vascular imaging endoscopes, a 7cm length vessel can be imaged in only one second.
Professor Wangyeol Oh said, “Our newly developed blood vessel endoscope system was tested by imaging a live animal’s blood vessels, which is similar to human blood vessels. The result was very successful.”
“Collaborating closely with hospitals, we are preparing to produce the imaging of an animal’s coronary arteries, which is similar in size to the human heart,” commented Professor Oh on the future clinical application and commercialization of the endoscope system. He added, “After such procedures, the technique can be applied in clinical patients within a few years.”
Professor Oh’s research was supported by the National Research Foundation of Korea and the Global Frontier Project by the Korean government. The research results were published in the 2014 January’s edition of Biomedical Optics Express.
Figure 1: End portion of optical endoscope (upper left)
Figure 2: High-speed optical scanning unit of the endoscope (top right)
Figure 3: High-resolution images of the inside of in vivo animal blood vessels (in the direction of vascular circumference and length)
Figure 4: High-resolution images of the inside of in vivo animal blood vessels (in the direction of the vein depth)
2014.03.25 View 10279 -
Opening Ceremony of Genetic Donguibogam held
- Medicine using traditional natural substances • Food product source technology development begins
- Over 150,000,000,000 Won for 10 years of work invested to develop source technology
- Opening ceremony held on November 26th at 3 p.m. in Bio & Brain Engineering Division Building
The research to develop medicine and food source technology using traditional natural substances hasbegun.The opening ceremony of the “Genetic Donguibogam” business group, with KAIST Department of Bio & Brain Engineering Professor Do Heon Lee as the leader, was held on November 26th at 3 p.m. in Dream Hall, Bio & Brain Engineering Division Building, KAIST, Daejeon. The attendees of the opening ceremony included Yo Eop Im, Head of the Future Technology Department of the Ministry of Science, ICT and Future Planning and around 200 experts in science and technology industry, including the National Research Foundation of Korea, KAIST, the Korea Institute of Science and Technology, Seoul National University and Yonsei University.
The business group was established to re-interpret traditional natural substances proved to be effective from experience and improve quality of life by researching its applications; and to develop integrated source technology using traditional natural substances. The group is to invest over 150,000,000,000 Won for 10 years of research to secure natural substance source technology in five stages: interpretation technology, analysis technology, verification technology, bio marker technology and human body effectiveness verification technology. Especially, the focus would be on the use of virtual body computer models and Omics* to analyse the effects of traditional natural substances mixture on human body, and to find new materials for healthcare.
This research model, it is hoped, will have a new item to pioneer in the world natural substance market as well as securing a technologically competitive edge in bio industry by developing source technology that investigates the effects of traditional natural substances using cutting edge science.
KAIST Department of Bio & Brain Engineering Professor and Head Do Heon Lee of the “Genetic Donguibogam” Business Group said, “We will push forward to develop source energy by integrating IT-BT technology with a computer virtual body to build a cooperation system with medicine and functional food industries.” He continued: “This will enable not only the creation of a new industry, but also customised medicine.”
The 12 partners of the group include KAIST, Korea Institute of Science and Technology, Seoul National University and Yonsei University and 200 experts. The research participation area will be widened to foreign research institutes and associated companies.
* Terminology
Noun) Omics is an academic discipline analysing mass information on metabolism of physiological phenomena in specific cells (transcriptome, proteome and protoplast) with an integrated approach to determine vital phenomena.
2013.12.11 View 8516 -
The key to Alzheimer disease, PET-MRI made in Korea
Professor Kyu-Sung Cho
- Simultaneous PET-MRI imaging system commercialization technology developed purely from domestic technology - - Inspiring achievement by KAIST, National NanoFab Center, Sogang University, Seoul National University Hospital –
Hopes are high for the potential of producing domestic products in the field of state-of-the-art medical imaging equipment that used to rely on imported products.
The joint research team (KAIST, Sogang University and Seoul National University) with KAIST Department of Nuclear and Quantum Engineering Professor Kyu-Sung Cho in charge, together with National Nanofab Institution (NNFC; Director Jae-Young Lee), has developed PET-MRI simultaneous imaging system with domestic technology only. The team successfully acquired brain images of 3 volunteers with the newly developed system.
PET-MRI is integrated state-of-the-art medical imaging equipment that combines the advantages of Magnetic Resonance Imaging (MRI) that shows anatomical images of the body and Position Emission Tomography (PET) that analyses cell activity and metabolism. Since the anatomical information and functional information can be seen simultaneously, the device can be used to diagnose early onset Alzheimer’s disease and is essential in biological science research, such as new medicine development.
The existing equipment used to take MRI and PET images separately due to the strong magnetic field generated by MRI and combine the images. Hence, it was time consuming and error-prone due to patient’s movement. There was a need to develop PET that functions within a magnetic field to create a simultaneous imaging system.
The newly developed integral PET-MRI has 3 technical characteristics: 1. PET detector without magnetic interference, 2. PET-MRI integration system, 3.PET-MRI imaging processing.
The PET detector is the most important factor and accounts for half the cost of the whole system. KAIST Professor Cho and NNFC Doctor Woo-Suk Seol’s team successfully developed the Silicon Photomultiplier (amplifies light coming into the radiation detector) that can be used in strong magnetic fields. The developed sensor has a global competitive edge since it optimises semiconductor processing to yield over 95% productivity and around 10% gamma radiation energy resolving power.
Sogang University Department and Electrical Engineering Professor Yong Choi developed cutting edge PET system using a new concept of electric charge signal transmission method and imaging location distinction circuit. The creativity and excellence of the research findings were recognised and hence published on the cover of Medical Physics in June.
Seoul National University Hospital Department of Nuclear Medicine Professor Jae-Sung Lee developed the Silicon Photomultiplier sensor based PET imaging reconstitution programme, MRI imaging based PET imaging revision technology and PET-MRI imaging integration software.
Furthermore, KAIST Department of Electrical Engineering Professor Hyun-Wook Park was responsible for the development of RF Shielding technology that enables simultaneous installation of PET and MRI and using this technology, he developed a head coil for the brain that can be connected to PET for installation.
Based on the technology describe above, the joint research team successfully developed PET-MRI system for brains and acquired PET-MRI integrated brain images from 3 volunteers last June.
In particular, this system has the distinct feature of a detachable PET module and MRI head coil to the existing whole body MRI, so that PET-MRI simultaneous imaging is possible with low installation cost.
Professor Cho said, “We have prepared the foundation of domestic commercial PET and the system has a competitive edge in the global market of PET-MRI system technology.” He continued, “It can reduce the cost of the increasing brain related disease diagnosis, including Alzheimer’s, dramatically.”
Funded by Ministry of Trade, Industry and Energy as an Industrial Foundation Technology Development Project (98 billion won in 7 years), the research applied for over 20 patents and 20 CSI theses.
Figure 1.Brain phantom images from developed PET-MRI system
Figure 2. Brain images from developed PET-MRI system
Figure 3. Domestic PET-MRI clinical trial
Figure 4. Head RF coil and PET detector inserted in MRI
Figure 5. Insertion type PET detector module
Figure 6. Silicon Photomultiplier sensor (Left) and flash crystal block (right)
Figure7. Silicon Photomultiplier sensor
Figure 8. PET detection principle
2013.11.28 View 12479 -
A magnetic pen for smartphones adds another level of conveniences
Utilizing existing features on smartphones, the MagPen provides users with a compatible and simple input tool regardless of the type of phones they are using.
A doctoral candidate at the Korea Advanced Institute of Science and Technology (KAIST) developed a magnetically driven pen interface that works both on and around mobile devices. This interface, called the MagPen, can be used for any type of smartphones and tablet computers so long as they have magnetometers embedded in.
Advised by Professor Kwang-yun Wohn of the Graduate School of Culture Technology (GSCT) at KAIST, Sungjae Hwang, a Ph.D. student, created the MagPen in collaboration with Myung-Wook Ahn, a master"s student at the GSCT of KAIST, and Andrea Bianchi, a professor at Sungkyunkwan University.
Almost all mobile devices today provide location-based services, and magnetometers are incorporated in the integrated circuits of smartphones or tablet PCs, functioning as compasses. Taking advantage of built-in magnetometers, Hwang"s team came up with a technology that enabled an input tool for mobile devices such as a capacitive stylus pen to interact more sensitively and effectively with the devices" touch screen. Text and command entered by a stylus pen are expressed better on the screen of mobile devices than those done by human fingers.
The MagPen utilizes magnetometers equipped with smartphones, thus there is no need to build an additional sensing panel for a touchscreen as well as circuits, communication modules, or batteries for the pen. With an application installed on smartphones, it senses and analyzes the magnetic field produced by a permanent magnet embedded in a standard capacitive stylus pen.
Sungjae Hwang said, "Our technology is eco-friendly and very affordable because we are able to improve the expressiveness of the stylus pen without requiring additional hardware beyond those already installed on the current mobile devices. The technology allows smartphone users to enjoy added convenience while no wastes generated."
The MagPen detects the direction at which a stylus pen is pointing; selects colors by dragging the pen across smartphone bezel; identifies pens with different magnetic properties; recognizes pen-spinning gestures; and estimates the finger pressure applied to the pen.
Notably, with its spinning motion, the MagPen expands the scope of input gestures recognized by a stylus pen beyond its existing vocabularies of gestures and techniques such as titling, hovering, and varying pressures. The tip of the pen switches from a pointer to an eraser and vice versa when spinning. Or, it can choose the thickness of the lines drawn on a screen by spinning.
"It"s quite remarkable to see that the MagPen can understand spinning motion. It"s like the pen changes its living environment from two dimensions to three dimensions. This is the most creative characteristic of our technology," added Sungjae Hwang.
Hwang"s initial research result was first presented at the International Conference on Intelligent User Interfaces organized by the Association for Computing Machinery and held on March 19-22 in Santa Monica, the US.
In the next month of August, the research team will present a paper on the MagPen technology, entitled "MagPen: Magnetically Driven Pen Interaction On and Around Conventional Smartphones" and receive an Honorable Mention Award at the 15th International Conference on Human-Computer Interaction with Mobile Devices and Services (MobileHCI 2013) to be held in Germany.
In addition to the MagPen, Hwang and his team are conducting other projects to develop different types of magnetic gadgets (collectively called "MagGetz") that include the Magnetic Marionette, a magnetic cover for a smartphone, which offers augmented interactions with the phone, as well as magnetic widgets such as buttons and toggle interface.
Hwang has filed ten patents for the MagGetz technology.
Youtube Links: http://www.youtube.com/watch?v=NkPo2las7wc, http://www.youtube.com/watch?v=J9GtgyzoZmM
2013.07.25 View 9930 -
Ligand Recognition Mechanism of Protein Identified
Professor Hak-Sung Kim
-“Solved the 50 year old mystery of how protein recognises and binds to ligands”
- Exciting potential for understanding life phenomena and the further development of highly effective therapeutic agent development
KAIST’s Biological Science Department’s Professor Hak-Sung Kim, working in collaboration with Professor Sung-Chul Hong of Department of Physics, Seoul National University, has identified the mechanism of how the protein recognizes and binds to ligands within the human body.
The research findings were published in the online edition of Nature Chemical Biology (March 18), which is the most prestigious journal in the field of life science.
Since the research identified the mechanism, of which protein recognises and binds to ligands, it will take an essential role in understanding complex life phenomenon by understanding regulatory function of protein.
Also, ligand recognition of proteins is closely related to the cause of various diseases. Therefore the research team hopes to contribute to the development of highly effective treatments.
Ligands, well-known examples include nucleic acid and proteins, form the structure of an organism or are essential constituents with special functions such as information signalling.
In particular, the most important role of protein is recognising and binding to a particular ligand and hence regulating and maintaining life phenomena. The abnormal occurrence of an error in recognition of ligands may lead to various diseases.
The research team focused on the repetition of change in protein structure from the most stable “open form” to a relatively unstable “partially closed form”.
Professor Kim’s team analysed the change in protein structure when binding to a ligand on a molecular level in real time to explain the ligand recognition mechanism.
The research findings showed that ligands prefer the most stable protein structure. The team was the first in the world to identify that ligands alter protein structure to the most stable, the lowest energy level, when it binds to the protein.
In addition, the team found that ligands bind to unstable partially-closed forms to change protein structure.
The existing models to explain ligand recognition mechanism of protein are “Induced Custom Model”, which involves change in protein structure in binding to ligands, and the “Structure Selection Model”, which argues that ligands select and recognise only the best protein structure out of many. The academic world considers that the team’s research findings have perfectly proved the models through experiments for the first time in the world.
Professor Kim explained, “In the presence of ligands, there exists a phenomenon where the speed of altering protein structure is changed. This phenomenon is analysed on a molecular level to prove ligand recognition mechanism of protein for the first time”. He also said, “The 50-year old mystery, that existed only as a hypothesis on biology textbooks and was thought never to be solved, has been confirmed through experiments for the first time.”
Figure 1: Proteins, with open and partially open form, recognising and binding to ligands.
Figure 2: Ligands temporarily bind to a stable protein structure, open form, which changes into the most stable structure, closed form. In addition, binding to partially closed form also changes protein structure to closed form.
2013.04.01 View 10385 -
KAIST and JAIT Sign MOU
KAIST and JAIT (Jeonbuk Institute of Automotive Technology) signed a MOU for the training and development of future automobile technology.
JAIT is the domestic front runner in automobile research and the MOU will allow KAIST to participate with JAIT on research and development of automobile technology.
Research on future vehicle technology, transportation system using electric transport system, cooperation in education, research and development, and international business, and knowledge transfer are all part of the MOU.
2012.11.29 View 6820 -
Dopant properties of silicon nanowires investigated
Professor Chang Kee Joo
Professor Kee Joo Chang’s research team from the Department of Physics at KAIST has successfully unearthed the properties of boron and phosphorous dopants in silicon nanowires, a material expected to be used in next generation semiconductors. The research team was the first in the world to investigate the movement of boron and phosphorous (impurities or ‘dopants’ added for electrical flow) in oxidized silicon nanowires and study the mechanism behind its deactivation.
It is nearly impossible to develop a silicon based semiconductor thinner than 10nm, even using the most advanced modern technology. However, the thickness of silicon nanowires are within the nano level and hence, allows a higher degree of integration in semiconductors.
For silicon nanowires to carry electricity, small amounts of boron and phosphorous need to be added (‘doping’ process). Compared to silicon, nanowires are harder to create due to the difficulties in the doping process as well as the control of electrical conduction properties.
Professor Chang’s research team improved upon the existing simple model by applying revolutionary quantum simulation theory to create a realistic core-shell atomic model. This research successfully investigated the cause of the escape of boron dopants from the silicon core during oxidation. It was also found that although phosphorous dopants do not escape as oxides, they form electrically deactivated pairs which decreases the efficiency. These phenomena were attributed to the film shape of the nano-wires, which increases the relative surface area compared to a same volume of silicon.
The research results were published in the online September edition of the world renowned Nano Letters.
Figure: The longitudinal section diagram of the Silicon/oxide core-shell model
2012.11.28 View 7544