Full-Text Search:
Home|Journal Papers|About CNKI|User Service|FAQ|Contact Us|中文
《Southwest China Journal of Agricultural Sciences》 2012-01
Add to Favorite Get Latest Update

Protein Expression Technologies,Structure,Activity and Evolution of Chalcone Synthase

CHEN Jun-yi1,CHAI You-rong1,YAO Yong-hong2 (1.Chongqing Key Laboratory of Crop Quality Improvement,Chongqing Rapeseed Engineer Research Centre,Key Laboratory of Biotechnology and Crop Quality Improvement of Ministry of Agriculture,College of Agronomy and Biotechnology,Southwest University,Chongqing 400716,China;2.Chongqing Academy of Agricultural Sciences,Chongqing 401329,China)  
The chalcone synthase(CHS) was the first-step key-enzyme of flavonoid pathway,participating in biosynthesis of all flavonoid and isoflavonoid compounds and determining many important plant traits.In NCBI,2917 CHS sequences were submitted and released.Within the genome of a single species,general CHS was encoded by a gene family which was generated by gene duplication.Currently CHS protein was mainly expressed in prokaryotic Escherichia coli using pET vector system from Novagen Company.The popular optimum parameters were to inoculate 3 h by 1mmol/L IPTG under 37 ℃.The expressed CHS protein was generally purified through His-Tag affinity purification,identified by mass chromatography or immunoassay,and activity-tested by HPLC analysis of the substrates and the products.X-ray crystal diffraction analysis was performed on CHS proteins from Medicago sativa etc.,and the three-dimensional structures of the protein and the active site were dissected,which were compared with those of other enzymes from plant type Ⅲ PKS superfamily.The catalytic center of CHS contained a Cys-His-Asn triad,and the CoA-binding tunnel and inner initiation/elongation/cyclization cavity were crucial for substrate specificity and elongation length of polyketides of CHS.Within plant type Ⅲ PKS superfamily,other enzymes shared similar backbone and catalytic manner with CHS,but the change of active-site residues might bring to the change of the structure of active center,thus cause significant change in substrate specificity,catalytic activity and product type,which was the basic force for protein-level evolution.
【Fund】: 重庆市科技攻关项目(CSTC 2009AB1030);; 国家“863”计划(2006AA10Z110);; 西南大学农生院本科生创新性研究项目共同资助
【CateGory Index】: Q943.2
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
©2006 Tsinghua Tongfang Knowledge Network Technology Co., Ltd.(Beijing)(TTKN) All rights reserved