Download YANG Keqian

Research Overview of the group of
Microbial Transformation and Catalysis
Prof. Dr. Ke-Qian Yang
Part I. Introduction
About the group: Microbial Transformation and Catalysis
The research group is led by Dr. Yang Ke-Qian. His research interests include
microbial physiology and development of microorganisms for biotransformation and
biocatalysis applications. The group is currently actively working on the identification
and characterization of novel enzymatic reactions and metabolic pathways;
characterization of protein complexs; and protein engineering.
About group leader and the group members
Dr. Yang graduated from the department of marine biology, Qingdao University
of Oceanography (Qingdao, Shandong) in 1985. Upon graduation, Dr. Yang passed
the national exam for students going abroad and was selected as government
sponsored graduate student to study abroad. He obtained his Ph. D. degree in 1993
from Dalhousie University (Halifax, Canada) under the supervision of professor Leo
C. Vining. And worked as postdoctoral fellow in the lab of Leo C. Vining from
1993-1996 and as research associate in the lab of Julian E. Davies from 1997-1999 at
University of British Columbia (Vancouver, Canada). During 1999-2001, he worked
briefly as senior scientist in FermaLogic Inc. (Chicago, USA), and finally joined
IM/CAS (Beijing, China) in 2001. He now serves on the board of several professional
associations and is the editor of “Chinese Journal of Biotechnology”.
The group includes 4 regular stuffs and 8 graduate students, among the stuffs 3
hold assistant professor title (Dr. Wang Sheng-Lan, Dr. Fan Ke-Qiang and Qia
Cui-Juan) one is senior technician (Han Hui).
Part II.
Background and Significance
We choose bacteria with complex life cycle and versatile catalytic potentials to
study bacterial physiology and important biotransformation and biocatalysis reactions
and the underlying catalytic and regulatory mechanisms. The model bacteria we used
are streptomycetes. The ultimate goal is to develop bacterial host to make desired
products.
Part III. Major Achievements
In the past 5 years, our lab grew from merely an office to a fully functional lab
with 15 members conducting active research. We have secured funding from major
funding agencies in China and made significant progress in our chosen research
directions.
1. Characterization of jadomycin biosynthetic pathway.
Polyketides is a group of medically important secondary metabolites produced by
bacteria and other organisms. Jadomycin is an atypical angucycline antibiotic, its
biotransformation requires a unique oxidative ring cleavage reaction not
previously studied or understood in nature.
This unique reaction could be
explored to make many new compounds (JACS, 2004). We studied 3 oxygenases
potentially involved in jadomycin biosynthesis (CBC, 2005), and demonstrated
that one of the oxygenase possesses oxygenase/dehydrase activity (JBC, 2005).
Our works will guide future studies of aromatic polyketide biosynthesis.
2. Biological activities of new jadomycin derivatives
We tested the activities of jadomycins agaist several human cancer cell lines and
found broad spectrum cytotoxic activities against these cell lines (Journal of
Antibiotics, in press).
We are currently generating more derivatives and
evaluating their activities and try to improve the yield of these compounds in a
fermentation process.
3. Engineering of penicillin expandase
China is the No. 1 producer of the commodity antibiotic penicillin in absolute
amount (35000 ton) but lacks the ability to convert it into value added products,
such as cephalosporins. A biotransformation process to convert penicillin to
cephalosporins is desirable. We used random mutagenesis, DNA shuffling and
structure guided mutagenesis to engineer penicillin expandase. After mutagenesis
and evaluation of the mutant enzymes, we identified several mutants with
improved properties (recognize alternative substrates, with better kinetics). One
paper was published (FEMS Microbiology Letters, 2005), another is being
prepared for AEM.
4. Functional studies of bacterial biosynthetic and regulatory complexs.
These works stem from our interests in bacterial physiology and our belief that
biological functions are performed by protein complex. In the past few years, we
have devoted much effort to establish techniques to isolate protein complex and
use the information on such complexes to understand mechanisms of biosynthesis
and regulation.
We also try to develop proteomic approaches to evaluate
metabolism. We have conducted preliminary study on inner membrane proteome
of Streptomyes coelicolor using MudPit platform and reported more than 100
membrane proteins (Chinese Journal of Biotechnology, in press). We are currently
characterizing several protein complexs.
Recent Publications:
1.
Zheng, J.-T., Rix, U., Zhao, L.-X., Mattingly, C., Adams, V., Chen, Q., Rohr, J. & Yang,
K.-Q. (2005) Cytotoxic activities of new jadomycin derivatives. The Journal of Antibiotics,
in press.
2.
Liu, J.-M. (柳金满), Yang, K.-Q. (杨克迁) (2005) Functional analyses of a TPR repeat
containing regulatory gene-tcrA in Streptomyces coelicolor. ACTA MICROBIOLOGICA
SINICA,in press.
3.
Shi, X.-M. (石宣明)，Luo, Y.-M. (罗元明)，Zhang, G.-F. (张贵锋)，Su, Z.-G. (苏志国)，
Huang, Y.-B. (黄玉碧)，Yang, K.-Q. (杨克迁) （2005）Analyses of Streptomyces coelicolor
Inner Membrane Proteome by Multidimentional Protein Identification Technology. Chinese
Journal of Biotechnology, in press.
4.
Chen, Y.-H., Wang, C.-C., Greenwell, L.M., Rix, U., Hoffmeister D., Vining, L.C., Rohr, J. &
Yang, K.-Q. (2005) Functional analyses of oxygenases in jadomycin biosynthesis and
identification of JadH as a bifunctional oxygenase/dehydrase. Journal of Biological
Chemistry, 280: 22508-22514.
5.
Wu, X.-B., Fan, K.-Q., Wang, Q.-H. & Yang, K.-Q. (2005) C-terminus mutations of
Acremonium chrysogenum deacetoxy/deacetylcephalosporin C synthase with improved
activity toward penicillin analogs. FEMS Microbiology Letters, 246: 103-110*.
6.
Rix, U., Wang, C.-C., Chen, Y.-H., Lipata, F. M., Rix, L. R., Greenwell, L.M.,
Vining, L.C.,
Yang, K.-Q. & Rohr, J. (2005) The oxidative ring cleavage in jadomycin biosynthesis: a
multistep oxygenation cascade in a biosynthetic black box. ChemBioChem. 6: 838-845*.
7.
Zuo, Y. (左妍)，Yang, K.-Q. (杨克迁) (2005) Construction of a tetracycline-GFP biosensor.
Chinese Journal of Biotechnology. 21:97-101
8.
Mo, H.-B. (莫宏波)，Bai, L.-Q. (白林泉)，Wang, S.-L. (王胜兰)，Yang, K.-Q. (杨克迁)
（2004）Construction of E. coli-strepromycete conjugal plasmids. Chinese Journal of
Biotechnology 20：662-666
9.
Rix, U., Zheng, J., Remsing, Rix L.L., Greenwell, L., Yang, K.-Q. & Rohr, J. (2004) The
dynamic structure of jadomycin B and the amino acid incorporation step of its biosynthesis.
Journal of the American Chemical Society, 126: 4496-4497.
Part IV.
Future Research Plan
In the next 5 years, our research efforts will still focus on bacterial physiology
using functional genomic approaches. We will choose several biosynthetic or
regulatory protein complexes as targets for detailed studies. On the applied side, we
have chosen several polyketide biosynthetic pathways and their products to study the
corresponding biosynthetic pathways, enzymatic reactions. We will also continue our
effort to modify key enzymes for biotransformation and biocatalysis purposes and to
modify the structure of interested small molecules. We will start developing 2
candidate natural product lead compounds for pre-clinical tests.