• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

1998 Fiscal Year Final Research Report Summary

Structural Studies on Degradation Mechanisn of Organohalides by Dehalogenase Using Protein-Engineering Techniques

Research Project

Project/Area Number 09660088
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 応用微生物学・応用生物化学
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

HATA Yasuo  Kyoto University, Institute for Chemical Research, Associate Professor, 化学研究所, 助教授 (10127277)

Project Period (FY) 1997 – 1998
Keywordsdehalogenase / X-ray crystal analysis / reaction intermediate / mutant enzyme / four-dimensional Structure / dehalogenation / SN2 reaction
Research Abstract

Dehalogenases for decomposing harmful organohalides must be developed as soon as possible to clean up environmental pollution. In the present research, structural studies at atomic level on mechanism of degrading substrates organohalides by Pseudomonas sp. YL L-2-haloacid dehalogenase, using protein-engineering techniques. The 2 * X-ray crystal structure analysis of the native enzyme has revealed that each subunit of the dimeric enzyme consists of two domains : the core-domain having a alpha/beta structure with the active site, and four-helix bundle domain for dimerization. Subsequently, 2 * crystal structures of complexes prepared by soaking the S175A mutant crystals in solutions of various substrates, L-2-haloacids, have revealed those of ester intermediates where the side-chain carboxyle oxygen is covalently bonded to the C2 atom of the substrate. In the intermediates, the region of Asp10-Thr14 moves towards the active site, and the substrates lose the halogen and change their configuration from L- to D-forms. In each case, moreover, a new water molecule has been found in the vicinity of the Serl75 hydroxyle. In case of the substrate L-2-haloamide, the electron density peak, which can be assigned as the halide ion released from the substrate, has occurred near the side chain of Arg41 which is expected to be involved in abstraction of the halogen from the substrate. In each intermediate, the carboxyle group of the substrate has been stabilized by hydrogen bonds with the Ser118 hydroxyle and the main-chain amino group of Asn119, and the arkyl group of the substrate has been stabilized byhydrophobic interactions in the hydrophobic pocket.

  • Research Products

    (1 results)

All Other

All Publications (1 results)

  • [Publications] 畑 安雄: "L-2-ハロ酸脱ハロゲン化酵素の立体構造と反応機構の解析" 日本結晶学会誌. 39. 358-365 (1997)

    • Description
      「研究成果報告書概要(和文)」より

URL: 

Published: 1999-12-08  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi