Biotechnology+Journal
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Mystery of Biological Plastic Synthesis Machinery Unveiled
Plastics and other polymers are used every day. These polymers are mostly made from fossil resources by refining petrochemicals. On the other hand, many microorganisms naturally synthesize polyesters known as polyhydroxyalkanoates (PHAs) as distinct granules inside cells.
PHAs are a family of microbial polyesters that have attracted much attention as biodegradable and biocompatible plastics and elastomers that can substitute petrochemical counterparts. There have been numerous papers and patents on gene cloning and metabolic engineering of PHA biosynthetic machineries, biochemical studies, and production of PHAs; simple Google search with “polyhydroxyalkanoates” yielded returns of 223,000 document pages. PHAs have always been considered amazing examples of biological polymer synthesis. It is astounding to see PHAs of 500 kDa to sometimes as high as 10,000 kDa can be synthesized in vivo by PHA synthase, the key polymerizing enzyme in PHA biosynthesis. They have attracted great interest in determining the crystal structure of PHA synthase over the last 30 years, but unfortunately without success. Thus, the characteristics and molecular mechanisms of PHA synthase were under a dark veil.
In two papers published back-to-back in Biotechnology Journal online on November 30, 2016, a Korean research team led by Professor Kyung-Jin Kim at Kyungpook National University and Distinguished Professor Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) described the crystal structure of PHA synthase from Ralstonia eutropha, the best studied bacterium for PHA production, and reported the structural basis for the detailed molecular mechanisms of PHA biosynthesis. The crystal structure has been deposited to Protein Data Bank in February 2016. After deciphering the crystal structure of the catalytic domain of PHA synthase, in addition to other structural studies on whole enzyme and related proteins, the research team also performed experiments to elucidate the mechanisms of the enzyme reaction, validating detailed structures, enzyme engineering, and also N-terminal domain studies among others.
Through several biochemical studies based on crystal structure, the authors show that PHA synthase exists as a dimer and is divided into two distinct domains, the N-terminal domain (RePhaC1ND) and the C-terminal domain (RePhaC1CD). The RePhaC1CD catalyzes the polymerization reaction via a non-processive ping-pong mechanism using a Cys-His-Asp catalytic triad. The two catalytic sites of the RePhaC1CD dimer are positioned 33.4 Å apart, suggesting that the polymerization reaction occurs independently at each site. This study also presents the structure-based mechanisms for substrate specificities of various PHA synthases from different classes.
Professor Sang Yup Lee, who has worked on this topic for more than 20 years, said,
“The results and information presented in these two papers have long been awaited not only in the PHA community, but also metabolic engineering, bacteriology/microbiology, and in general biological sciences communities. The structural information on PHA synthase together with the recently deciphered reaction mechanisms will be valuable for understanding the detailed mechanisms of biosynthesizing this important energy/redox storage material, and also for the rational engineering of PHA synthases to produce designer bioplastics from various monomers more efficiently.”
Indeed, these two papers published in Biotechnology Journal finally reveal the 30-year mystery of machinery of biological polyester synthesis, and will serve as the essential compass in creating designer and more efficient bioplastic machineries.
References:
Jieun Kim, Yeo-Jin Kim, So Young Choi, Sang Yup Lee and Kyung-Jin Kim. “Crystal structure of Ralstonia eutropha polyhydroxyalkanoate synthase C-terminal domain and reaction mechanisms” Biotechnology Journal DOI: 10.1002/biot.201600648
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600648/abstract
Yeo-Jin Kim, So Young Choi, Jieun Kim, Kyeong Sik Jin, Sang Yup Lee and Kyung-Jin Kim. “Structure and function of the N-terminal domain of Ralstonia eutropha polyhydroxyalkanoate synthase, and the proposed structure and mechanisms of the whole enzyme” Biotechnology Journal DOI: 10.1002/biot.201600649
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600649/abstract
2016.12.02 View 9013 -
International Science Journal Spotlights Korean Biotechnology
Biotechnology Journal published by German-based Wiley-VCH, one of the world"s major scientific and technical publishers, devoted its entire special edition for May to biotechnology in Korea.
The monthly journal"s special issue was planned by KAIST Professor Sang-Yup Lee of the Chemical and Biomolecular Engineering Department who is one of the journal"s two editors-in-chief.
The special issue outlines the current status and future prospect of biotechnology in Korea, and presents five review papers and eight original papers by leading Korean biotech researchers to showcase recent developments in Korean biotechnology. Among these papers, a review by Dr. Byung-Hwan Hyeon and his colleagues describes in detail the Korean biotechnology strategies represented by "Bio-Vision 2016," and another by Dr. Ji-Hyun Kim and his collaborators presents recent progress in microbial genome projects in Korea.
In the editorial of the journal, Prof. Lee said, "Heavy industry and IT industry have been the two drivers of Korean economic growth. Korea is now considering biotechnology as its next generation growth engine."
Underscoring the growing importance of fusion research, he mentioned that integration of biotechnology with information technology and nanotechnology is advancing rapidly in Korea. Another special edition of Biotechnology Journal focusing on these exciting biotech developments in Korea is planned for the future.
2008.05.20 View 12855 -
Prof. Sang-Yup Lee Co-Editor-in-Chief of Biotechnology Journal
Prof. Sang-Yup Lee of KAIST"s Department of Chemical and Biomolecular Engineering has been appointed as co-editor-in-chief of Biotechnology Journal published by Wiley-VCH, a German-based leading technical publisher, university authorities said Tuesday, April 15.
Launched in January 2006, Biotechnology Journal has covered biological process, brain ailments, biological medicine, protein design and other applied bio-sciences.
Starting in May, Lee will be responsible for setting and overseeing editorial direction of the journal along with Prof. Alois Jungbauer of Austria.
Professor Lee has been gaining recognition in and outside the country for his research on metabolic engineering. In 2002, he was chosen as one of Asia"s next generation leaders by the World Economic Forum. In 2007, Lee was elected a fellow of the American Association for the Advancement of Science, the world"s largest general scientific society. He is also serving as an editorial member of more than ten international journals including Biotechnology & Bioengineering.
Awards and honors include the First Young Scientist"s Award from the President of Korea, the Scientist of the Month Award from the Korean Ministry of Science and Technology, the Best Patent Award from Korean Intellectual Property Office, the Citation Classic Award from ISI, USA, and the First Elmer Gaden Award (1999 Best Paper Award) from Biotechnology and Bioengineering (John Wiley & Sons, USA) at the ACS National meeting.
2008.04.16 View 12819 -
Professor Sang-Yup Lee Senior Editor of U.S. Biotechnology Journal
Professor Sang-Yup Lee Named Senior Editor of U.S. Biotechnology Journal
Will supervise paper examination in the fields of system biology, system bioengineering and
metabolic engineering, and set editing direction
Professor Sang-Yup Lee, LG Chemical’s Chair-Professor and the leader of BK project group of KAIST Chemical and Biomolecular Engineering Department, was named senior editor of Biotechnology Journal published by the U.S. Wiley-VCH.
Professor Lee will supervise paper examination in the fields of system biology, system bioengineering and metabolic engineering, and set and manage the editing direction of the journal.
‘Biotechnology Journal’ was first published in January 2006 to exchange rapidly-exchanging knowledge and information in life science and its relevant fields by Wiley, a world-famous science journal publisher with the history of 208 years (founded in 1799). Particularly, ‘Biotechnology Journal’ is a new-typed scientific journal treating various fields such as life science research-relevant ethics and cultures necessary for general people as well as expertise research information of life science.
“Although taking charge of editing of many scientific journals spends much time, it’s very fruitful that I’ll lead the direction of research papers of many world-famous scientific journals and I can make efforts to prevent outstanding papers by Korean scientists from being disadvantaged,” said Professor Lee.
“More Korean scholars are taking charge of editing jobs of world-famous scientific journals. It’s a good indication that the capacities of Korean science and engineering have been enhanced significantly as much,” a staff of KAIST PR team said.
Meanwhile, Professor Lee, distinguished by outstanding research performances in the fields of metabolic engineering and system life engineering, is now ▲associate editor of Biotechnology and Bioengineering, top scientific journal of biotech engineering published by the U.S. Wiley ▲editor of Applied Microbiology and Biotechnology published by German Springer ▲ associate editor of Bioprocess and Biosystems Engineering by German Springer, and editing member of ▲ Journal of Bioinformatics and Computational Biology by Singapore’s World Scientific ▲ Asia Pacific Biotech News ▲ Biochemical Engineering Journal, Metabolic Engineering, and Microbial Cell Factory by Elsevier.
2007.02.02 View 14006