NISCAIR Online Periodicals Repository

Research Journals >
Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.39 [2002] >
IJBB Vol.39(5) [October 2002] >

Title: Contrasting effects of mutating active site residues, Aspartic acid 64 and Histidine 187 of Escherichia coli uracil-DNA glycosylase on uracil excision and interaction with an inhibitor protein
Authors: Handa, Priya
Acharya, Narottam
Talawar, Ramappa K
Roy, Sudipta
Varshney, Umesh
Issue Date: Oct-2002
Publisher: NISCAIR-CSIR, India
Abstract: Uracil, a promutagenic base, arises in DNA by spontaneous deamination of cytosine or by the malfunctioning of DNA polymerases. To maintain the genomic integrity, cells possess a highly conserved base excision repair enzyme. uracil –DNA glycosylase (UDG). UDGs have a notably high turnover number and strict specificity for uracil in DNA. UDGs are inhibited by a small proteinaceous inhibitor. Ugi, which acts as a transition state substrate mimic. Crystal structure studies have identified the residues crucial in catalysis, and in their interaction with Ugi. Here, we report on the  mutational analyses of  D64(D64H and D64N) and H187 (H187C, H187L and H187R) in the active site pocket of Escherichia coli UDG. The mutants were compromised in uracil excision by ~ 200-25,000 fold when compared to the native protein. In contrast. our analysis of the in vivo formed UDG-Ugi complexes on urea gels shows that D64 and H187 contribute minimally to the interaction of the two proteins. Thus, our findings prov de further evidence to the primary functi on of D64 and H187 in catalysis.
Page(s): 312-317
CC License:  CC Attribution-Noncommercial-No Derivative Works 2.5 India
ISSN: 0975-0959 (Online); 0301-1208 (Print)
Source:IJBB Vol.39(5) [October 2002]

Files in This Item:

File Description SizeFormat
IJBB 39(5) 312-317.pdf1.43 MBAdobe PDFView/Open
 Current Page Visits: 420 
Recommend this item


Online Submission of Articles |  NISCAIR Website |  National Knowledge Resources Consortium |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2015 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 168409 since 01-Sep-2015  Last updated on 29-Jun-2016Webmaster: