communication
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Discovery of Redox-Switch of KEenzyme Involved in N-Butanol Biosynthesis
Research teams at KAIST and Kyungpook National University (KNU) have succeeded in uncovering the redox-switch of thiolase, a key enzyme for n-butanol production in Clostridium acetobutylicum, one of the best known butanol-producing bacteria.
Biological n-butanol production was first reported by Louis Pasteur in 1861, and the bioprocess was industrialized usingClostridium acetobutylicum. The fermentation process by Clostridium strains has been known to be the most efficient one for n-butanol production. Due to growing world-wide issues such as energy security and climate change, the biological production of n-butanol has been receiving much renewed interest. This is because n-butanol possesses much better fuel characteristics compared to ethanol, such as higher energy content (29.2 MJ/L vs 19.6 MJ/L), less corrosiveness, less hygroscopy, and the ease with which it can be blended with gasoline and diesel.
In the paper published in Nature Communications, a broad-scope, online-only, and open access journal issued by the Nature Publishing Group (NPG), on September 22, 2015, Professor Kyung-Jin Kim at the School of Life Sciences, KNU, and Distinguished Professor Sang Yup Lee at the Department of Chemical and Biomolecular Engineering, KAIST, have proved that the redox-switch of thiolase plays a role in a regulation of metabolic flux in C. acetobutylicum by using in silico modeling and simulation tools.
The research team has redesigned thiolase with enhanced activity on the basis of the 3D structure of the wild-type enzyme. To reinforce a metabolic flux toward butanol production, the metabolic network of C. acetobutylicum strain was engineered with the redesigned enzyme. The combination of the discovery of 3D enzyme structure and systems metabolic engineering approaches resulted in increased n-butanol production in C. acetobutylicum, which allows the production of this important industrial chemical to be cost competitive.
Professors Kim and Lee said, "We have reported the 3D structure of C. acetobutylicum thiolase-a key enzyme involved in n-butanol biosynthesis, for the first time. Further study will be done to produce butanol more economically on the basis of the 3D structure of C. acetobutylicum thiolase."
This work was published online in Nature Communications on September 22, 2015.
Reference: Kim et al. "Redox-switch regulatory mechanism of thiolase from Clostridium acetobutylicum," Nature Communications
This research was supported by the Technology Development Program to Solve Climate Changes from the Ministry of Education, Science and Technology (MEST), Korea, the National Research Foundation of Korea, and the Advanced Biomass Center through the Global Frontier Research Program of the MEST, Korea.
For further information, contact Dr. Sang Yup Lee, Distinguished Professor, KAIST, Daejeon, Korea (leesy@kaist.ac.kr, +82-42-350-3930); and Dr. Kyung-Jin Kim, Professor, KNU, Daegu, Korea (kkim@knu.ac.kr, +82-53-950-6088).
Figure 1: A redox-switch of thiolase involves in butanol biosynthesis in Clostridium acetobutylicum. Thiolase condenses two acetyl-CoA molecules for initiating four carbon flux towards butanol.
Figure 2: Thiolase catalyzes the condensation reaction of acetyl-CoA to acetoacetyl-CoA. Two catalytic cysteine residues at 88th and 378th are oxidized and formed an intermolecular disulfide bond in an oxidized status, which results in inactivation of the enzyme for n-butanol biosynthesis. The intermolecular disulfide bond is broken enabling the n-butanol biosynthesis, when the environment status is reduced.
2015.09.23 View 9823 -
KAIST and Chongqing University of Technology in China Open an International Program
With the help of KAIST, Chongqing University of Technology (CQUT) in China established an electrical engineering and computer science program and admitted their first 66 freshmen this fall semester.
The joint program was created to foster skilled engineers in the fields of electrical engineering and computer science, which are necessary for the development of the Korean and Chinese Industrial Complex located in Chongqing City.
KAIST has provided CQUT with a majority of the program’s curricula currently offered to its students in Daejeon, Korea.
Under the jointly administered program, KAIST takes on education and research while CQUT is responsible for student selection and administration.
KAIST has dispatched eight professors to teach the related fields in English, and 17 CQUT professors will teach the rest of the curricula.
In August 2014, KAIST and CQUT singed a cooperation agreement for education and research exchange and created the CQUT-KAIST Education Cooperation Center, which is headed by Professor Young-Nam Han of the Electrical Engineering Department at KAIST.
The two universities will expand their collaboration to include graduate programs by 2016.
In the picture below, President Steve Kang of KAIST (right) shakes hands with President Shi Xiaohui of Chongqing University of Technology (left).
2015.09.17 View 8626 -
Affordable Genetic Diagnostic Technique for Target DNA Analysis Developed
Professor Hyun-Gyu Park of the Department of Chemical and Biomolecular Engineering at KAIST has developed a technique to analyze various target DNAs using an aptamer, a DNA fragment that can recognize and bind to a specific protein or enzyme. This technique will allow the development of affordable genetic diagnoses for new bacteria or virus, such as Middle Ease Respiratory Syndrome (MERS). The research findings were published in the June issue of Chemical Communications, issued by the Royal Society of Chemistry in the United Kingdom. The paper was selected as a lead article of the journal.
The existing genetic diagnosis technique, based on molecular beacon probes, requires a new beacon probe whenever a target DNA mutates. As a result, it was costly to analyze various target DNA fragments. To address this problem, Professor Park’s team designed an aptamer that binds and deactivates DNA polymerase. The technique was used in reverse, so that the aptemer did not bind to the polymerase, maintaining its activated state, only if the target DNA was present. These probes are called TagMan probes.
The controlled activation and deactivation of DNA polymerase enables nucleic acid to elongate or dwindle, making it possible to measure fluorescence signals coming from TaqMan probes. This same probe can be used to detect various target DNAs, leading to the development of a new and sensitive genetic diagnostic technique.
Unlike the existing molecular beacon probe technique which requires a new probe for every target DNA, this new technique uses the same fluorescent TaqMan probe, which is cheaper and easier to detect a number of different target nucleic acid fragments. The application of this technique will make the process of identifying and detecting foreign DNAs from pathogens such as virus and bacteria more affordable and simple.
Professor Park said, “This technique will enable us to develop simpler diagnostic kits for new pathogens, such as MERS, allowing a faster response to various diseases. Our technology can also be applied widely in the field of genetic diagnostics.”
Picture: A schematic image of target nucleic acid extracted through the activation and deactivation of DNA polymerase
2015.07.31 View 9580 -
International Undergraduate Conference ICISTS-KAIST 2015 and ICISTS-KAIST Public Colloquium Held on August 3, 2015 at KAIST
The ICISTS-KAIST 2015, an international conference organized by a student organization called the International Conference for the Integration of Science, Technology, and Society at KAIST, was held from August 3rd to 7th at the KAIST campus and ICC Hotel in Daejeon. This year’s conference theme was “Shaping the Future.” Over 300 undergraduate students from more than 20 countries joined the event. The conference offered opportunities to explore emerging issues in science and technology, particularly in the fields of robotics, medicine, and science communication.
Vitalic Buterin, a rising scientist who received the 2014 World Technology Award for his development of the Ethereum Project, and Alan Irwin, a renowned scholar in science communication at the Copenhagen Business School in Denmark, were invited as keynote speakers. The list of other speakers included Stefan Lorenz Sorgner, the Director and Co-founder of the Beyond Humanism Network; Wendell Wallach, a scholar at Yale University's Interdisciplinary Center for Bioethics; and Hideto Nakajima, a professor at the Department of History, Philosophy and Social Studies of Science and Technology at Tokyo Institute of Technology.
As part of the ICISTS-KAIST 2015, ICISTS also hosted a public colloquium on August 5, 2015 at the Science Hall in Daejeon National Science Museum. Ko San, the Director of TIDE Institute; Hyo-Joon Woo, the Chief Executive Officer of Fransen; and Dong-Il Jung, the Chief Executive Officer of iDrone participated as the speakers.
2015.07.29 View 6668 -
KAIST Undergraduates Organize the Largest Interdisciplinary Conference in Asia
The largest interdisciplinary conference in Asia hosted by KAIST undergraduates for students around the world will be held in KAIST. The organizing committee of International Conference for the Integration of Science, Technology and Society (ICISTS) will hold the ICISTS-KAIST 2015 in KAIST and Hotel ICC from August 3-7, 2015, with around 300 Korean and international participants.
ICISTS-KAIST was established in 2005 to provide an annual platform for students to discuss the integration and the convergence of science, technology and society, regardless of their academic background.
This year’s theme is "Shaping the Future" and the topics for the conference are robotics, medicine, and science communication.
The keynote speakers are Vitalic Buterin, the winner of the World Technology Award in 2014 for the co-creation and invention of Ethereum and Alan Irwin, a well-known scholar of science, technology and society as well as the Dean of Research at the Copenhagen Business School in Denmark.
Other notable speakers include Adam Marcus, a professor of Hematology and Medical Oncology, Emory University School of Medicine; Stefan Lorenz Sorgner, the Director and co-founder of Beyond Humanism Network; Hideto Nakajima, a professor in the Department of History, Philosophy and Social Studies of Science and Technology at Tokyo Institute of Technology; Wendell Wallach, a lecturer at the Yale University Interdisciplinary Center for Bioethics; Jinil Lee, a professor in the Division of Biological Science and Technology at Yonsei University; and Sangwook Kim, an editor of APCTP web journal Crossroads and a professor in the Department of Physics Education, Pusan National University.
Last year, more than 300 students from 50 different countries attended the ICISTS-KAIST 2014 as delegates to exchange their thoughts and ideas on science, technology, and society.
To register for the event, please visit www.icists.org.
2015.07.14 View 7162 -
Professor Jae Kyu Lee Appointed the President of Association for Information Systems
Chair Professor Jae Kyu Lee of KAIST’s College of Business was appointed the President of Association for Information Systems (AIS) on July 1, 2015. Professor Lee will serve a one-year term, which will end in June 2016. With four thousand members researching information systems from 90 different nations, AIS is the largest academic society in the fields of information system and business process engineering.
Professor Lee has proposed his idea of “the Bright Internet” as the official vision of AIS. Employing this vision, AIS will create technology and systems, as well as sponsor international cooperation to solve fundamental issues of the Internet including concerns over hacking and cyber-related crimes.
The extent of damage from cyber-related crimes grows each year. Every day, 56 billion junk emails are sent to computers which are hacked and become “zombie” computers. The social cost of such crimes is estimated to be 400 billion US dollars annually.
Based on "the Bright Internet," AIS will build a preventative Internet security system by adopting ground rules that make attackers responsible for the damages from such crimes. The system will also modify technology and other systems to minimize privacy infringement while maintaining security. Finally, the Bright Internet proposes to adopt an international standard for this security system through collaboration with the International Telecommunications Union (ITU).
Professor Lee said, “The vision of the Bright Internet started from an awareness that we needed to resolve issues such as Internet addiction, indiscriminate media exposure, and verbal violence. This vision developed by the experts from all around the world will not only bring a revolution of a reliable Internet platform to a global scale but also reshape the Korean Internet platform.”
2015.07.02 View 6784 -
KAIST Professor Sung-Ju Lee Appointed a Technical Program Chair of INFOCOM
Professor Sung-Ju Lee of the Department of Computer Science at KAIST has been appointed to serve as a technical program chair of IEEE INFOCOME. The computer communication conference, started in 1982, is influential in the research fields of the Internet, wireless, and data centers.
Professor Lee is the first Korean to serve as a program chair. He has been acknowledged for his work in network communications. In the 34th conference, which will be held next year, he will take part in selecting 650 experts in the field to become members and supervise the evaluation of around 1,600 papers.
Professor Lee is the leading researcher in the field of wireless mobile network systems. He is a fellow of the Institute of Electrical and Electronics Engineers (IEEE) and served as the general chair of the 20th Association for Computing Machinery (ACM) SIGMOBILE Annual International Conference on Mobile Computing & Networking (MobiCom 2014). He is on the editorial boards of IEEE Transactions on Mobile Computing (TMC) and IEEE Internet of Things Journals.
Professor Lee said, “I hope to continue the traditions of the conference, as well as integrating research from various areas of network communication. I will strive to create a program with high technology transfer probability.”
The 34th IEEE INFOCOM will take place in San Francisco in April 2016.
2015.07.02 View 7334 -
Novel Photolithographic Technology Enabling 3D Control over Functional Shapes of Microstructures
Professor Shin-Hyun Kim and his research team in the Department of Chemical and Biomolecular Engineering at KAIST have developed a novel photolithographic technology enabling control over the functional shapes of micropatterns using oxygen diffusion.
The research was published online in the March 13th issue of Nature Communications and was selected as a featured image for the journal.
Photolithography is a standard optical process for transferring micropatterns on to a substrate by exposing specific regions of the photoresist layer to ultraviolet (UV) light. It is used widely throughout industries that require micropatterns, especially in the semiconductor manufacturing industry.
Conventional photolithography relied on photomasks which protected certain regions of the substrate from the input UV light. Areas covered by the photomasks remain intact with the base layer while the areas exposed to the UV light are washed away, thus creating a micropattern. This technology was limited to a two-dimensional, disc-shaped design as the boundaries between the exposed and roofed regions are always in a parallel arrangement with the direction of the light.
Professor Kim’s research team discovered that: 1) the areas exposed to UV light lowered the concentration of oxygen and thus resulted in oxygen diffusion; and 2) manipulation of the diffusion speed and direction allowed control of the growth, shape and size of the polymers. Based on these findings, the team developed a new photolithographic technology that enabled the production of micropatterns with three-dimensional structures in various shapes and sizes.
Oxygen was considered an inhibitor during photopolymerization. Photoresist under UV light creates radicals which initialize a chemical reaction. These radicals are eliminated with the presence of oxygen and thus prevents the reaction. This suggests that the photoresist must be exposed to UV light for an extended time to completely remove oxygen for a chemical reaction to begin.
The research team, however, exploited the presence of oxygen. While the region affected by the UV light lowered oxygen concentration, the concentration in the untouched region remained unchanged. This difference in the concentrations caused a diffusion of oxygen to the region under UV light.
When the speed of the oxygen flow is slow, the diffusion occurs in parallel with the direction of the UV light. When fast, the diffusion process develops horizontally, outward from the area affected by the UV light. Professor Kim and his team proved this phenomenon both empirically and theoretically. Furthermore, by injecting an external oxygen source, the team was able to manipulate diffusion strength and direction, and thus control the shape and size of the polymer. The use of the polymerization inhibitors enabled and facilitated the fabrication of complex, three-dimensional micropatterns.
Professor Kim said, “While 3D printing is considered an innovative manufacturing technology, it cannot be used for mass-production of microscopic products. The new photolithographic technology will have a broad impact on both the academia and industry especially because existing, conventional photolithographic equipment can be used for the development of more complex micropatterns.” His newest technology will enhance the manufacturing process of three-dimensional polymers which were considered difficult to be commercialized.
The research was also dedicated to the late Professor Seung-Man Yang of the Department of Chemical and Biomolecular Engineering at KAIST. He was considered one of the greatest scholars in Korea in the field of hydrodynamics and colloids.
Picture 1: Featured Image of Nature Communications, March 2015
Picture 2: Polymers with various shapes and sizes produced with the new photolithographic technology developed by Professor Kim
2015.04.06 View 9693 -
Qualcomm Innovation Award Recognizes 20 KAIST Students
The
award provides research fellowships, worth of USD 100,000, to 20 KAIST graduate
students
With an audience of 100 people present,
KAIST held a ceremony for the Qualcomm Innovation Award 2015 at the Information
Technology Convergence building on campus on March 12, 2015.
The Qualcomm Innovation Award, established
in 2010, is a fellowship that supports innovative science and engineering master’s
and doctoral students at KAIST. Qualcomm donated USD 100,000 to KAIST, stipulating that it be used to foster a creative research environment for graduate
students.
To select the recipients, KAIST formed an award committee chaired
by Professor Soo-Young Lee of the Department of Electrical Engineering and accepted research proposals until late January.
The award committee first selected 37
proposals from 75 papers submitted and then chose the final 20 research
proposals on March 12, 2015 after presentation evaluations. The presentations had to show promise of innovation and creativity; prospective influence on wireless communications
and mobile industry; and the prospect of being implemented.
Each recipient received a USD 4,500 research
fellowship along with an opportunity to present their research findings at a
workshop where Qualcomm engineers and other distinguished individuals of the industry
will attend.
Previously, Qualcomm has donated
research fellowships to KAIST graduate students in 2011 and 2013.
2015.03.19 View 9083 -
Press Release on Piezoelectric Nanogenerators of ZnO with Aluminium Nitride Stacked Layers by the American Institute of Physics
The
American Institute of Physics (AIP) released a news article entitled “Zinc
Oxide Materials Tapped for Tiny Energy Harvesting Devices” on January 13, 2015.
The
article described the research led by Professor Giwan Yoon of the
Electrical Engineering Department at KAIST. It was published in the January
12, 2015 issue of Applied Physics Letters.
AIP publishes the journal. For the news release, please visit the
link below:
The American
Institute of Physics, January 13, 2015
“Zinc
Oxide Materials Tapped for Tiny Energy Harvesting Devices”
New research helps
pave the way toward highly energy-efficient zinc oxide-based micro energy
harvesting devices with applications in portable communications, healthcare and
environmental monitoring, and more
http://www.aip.org/publishing/journal-highlights/zinc-oxide-materials-tapped-tiny-energy-harvesting-devices
2015.02.04 View 31613 -
A Key Signal Transduction Pathway Switch in Cardiomyocyte Identified
A KAIST research team has identified the fundamental principle in deciding the fate of cardiomyocyte or heart muscle cells. They have determined that it depends on the degree of stimulus in β-adrenergic receptor signal transduction pathway in the cardiomyocyte to control cells' survival or death. The findings, the team hopes, can be used to treat various heart diseases including heart failure.
The research was led by KAIST Department of Bio and Brain Engineering Chair Professor Kwang-Hyun Cho and conducted by Dr. Sung-Young Shin (lead author) and Ph.D. candidates Ho-Sung Lee and Joon-Hyuk Kang. The research was conducted jointly with GIST (Gwangju Institute of Science and Technology) Department of Biological Sciences Professor Do-Han Kim’s team. The research was supported by the Ministry of Science, ICT and Future Planning, Republic of Korea, and the National Research Foundation of Korea. The paper was published in Nature Communications on December 17, 2014 with the title, “The switching role of β-adrenergic receptor signalling in cell survival or death decision of cardiomyocytes.”
The β-adrenergic receptor signal transduction pathway can promote cell survival (mediated by β2 receptors), but also can result in cell death by inducing toxin (mediated by β1 receptors) that leads to various heart diseases including heart failure. Past attempts to identify the fundamental principle in the fate determining process of cardiomyocyte based on β-adrenergic receptor signalling concluded without much success.
The β-adrenergic receptor is a type of protein on the cell membrane of cardiomyocyte (heart muscle cell) that when stimulated by neurohormones such as epinephrine or norepinephrine would transduce signals making the cardiomyocyte contract faster and stronger.
The research team used large-scale computer simulation analysis and systems biology to identify ERK* and ICER** signal transduction pathways mediated by a feed-forward circuit as a key molecular switch that decides between cell survival and death.
Weak β-adrenergic receptor stimulations activate ERK signal transduction pathway, increasing Bcl-2*** protein expression to promote cardiomyocyte survival. On the other hand, strong β-adrenergic receptor stimulations activate ICER signal transduction pathway, reducing Bcl-2 protein expression to promote cardiomyocyte death.
Researchers used a systems biology approach to identify the mechanism of B-blocker****, a common drug prescribed for heart failure. When cardiomyocyte is treated with β1 inhibitor, strong stimulation on β-adrenergic receptor increases Bcl-2 expression, improving the chance of cardiomyocyte survival, a cell protection effect.
Professor Kwang-Hyun Cho said, “This research used systems biology, an integrated, convergence research of IT (information technology) and BT (biotechnology), to successfully identify the mechanism in deciding the fate of cardiomyocytes based on the β-adrenergic receptor signal transduction pathway for the first time. I am hopeful that this research will enable the control of cardiomyocyte survival and death to treat various heart diseases including heart failure.”
Professor Cho’s team was the first to pioneer a new field of systems biology, especially concerning the complex signal transduction network involved in diseases. Their research is focused on modelling, analyzing simulations, and experimentally proving signal pathways. Professor Cho has published 140 articles in international journals including Cell, Science, and Nature.
* ERK (Extracellular signal-regulated kinases): Signal transduction molecule involved in cell survival
** ICER (Inducible cAMP early repressor): Signal transduction molecule involved in cell death
*** Bcl-2 (B-cell lymphoma 2): Key signal transduction molecule involved in promotion of cell survival
**** β-blocker: Drug that acts as β-adrenergic receptor inhibitor known to slow the progression of heart failure, hence used most commonly in medicine.
Picture: A schematic diagram for the β-AR signalling network
2015.01.05 View 12264 -
Broadband and Ultrathin Polarization Manipulators Developed
Professor Bumki Min from the Department of Mechanical Engineering at KAIST has developed a technology that can manipulate a polarized light in broadband operation with the use of a metamaterial.
It is expected that this technology will lead to the development of broadband optical devices that can be applied to broadband communication and display.
When an object or its structure is analyzed by using a polarized light such as a laser, the results are generally affected by the polarized state of the light. Therefore, in an optics laboratory, the light is polarized by various methods.
In such cases, researchers employ wave plates or photoactive materials. However, the performance of these devices depend vastly on wavelength, and so they are not suitable to be used as a polarizer, especially in broadband.
There were many attempts to make artificial materials that are very photoactive by using metamaterials which have a strong resonance. Nonetheless, because the materials had an unavoidable dispersion in the resonance frequency, they were not adequate for broadband operation.
Professor Min’s research team arranged and connected helical metamaterials that are smaller than the wavelength of light. They verified theoretically and experimentally that polarized light can be constantly rotated regardless of the wavelength by super-thin materials that have thickness less than one-tenth of the wavelength of the light. The experiment which confirmed the theory was conducted in the microwave band.
Broadband polarized rotational 3D metamaterials were found to rotate the polarized microwave within the range of 0.1 GHz to 40 GHz by 45 degrees regardless of its frequency. This nondispersive property is quite unnatural because it is difficult to find a material that does not change in a wide band.
In addition, the research team materialized the broadband nondispersive polarized rotational property by designing the metamaterial in a way that it has chirality, which determines the number of rotations proportional to the wavelength.
Professor Min said, “As the technology is able to manipulate ultrathin polarization of light in broadband, it will lead to the creation of ultra-shallow broadband optical devices.”
Sponsored by the Ministry of Science, ICT and Future Planning of the Republic of Korea and the National Research Foundation of Korea, this research was led by a PhD candidate, Hyun-Sung Park, under the guidance of Professor Min. The research findings were published online in the November 17th issue of Nature Communications.
Figure 1 – Broadband and Ultrathin Polarization Manipulators Produced by 3D Printer
Figure 2 – Concept of Broadband and Ultrathin Polarization Manipulators
2014.12.03 View 10486