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Titolo:
CATALYTIC MECHANISM AND DNA SUBSTRATE RECOGNITION OF ESCHERICHIA-COLIMUTY PROTEIN
Autore:
LU AL; YUEN DS; CILLO J;
Indirizzi:
UNIV MARYLAND,SCH MED,DEPT BIOCHEM & MOL BIOL BALTIMORE MD 21201
Titolo Testata:
The Journal of biological chemistry
fascicolo: 39, volume: 271, anno: 1996,
pagine: 24138 - 24143
SICI:
0021-9258(1996)271:39<24138:CMADSR>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
ENZYME ENDONUCLEASE-III; BASE-PAIR; NUCLEOTIDE-SEQUENCE; MISMATCH REPAIR; SACCHAROMYCES-CEREVISIAE; MOLECULAR-CLONING; DAMAGED BASE; GENE-PRODUCT; CHROMOSOME-I; GLYCOSYLASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
57
Recensione:
Indirizzi per estratti:
Citazione:
A.L. Lu et al., "CATALYTIC MECHANISM AND DNA SUBSTRATE RECOGNITION OF ESCHERICHIA-COLIMUTY PROTEIN", The Journal of biological chemistry, 271(39), 1996, pp. 24138-24143

Abstract

Escherichia coli MutY protein cleaves A/G- or A/7,8-dihydro-8-oxo-guanine (A/GO)-containing DNA on the A-strand by N-glycosylase and apurinic/apyrimidinic endonuclease or lyase activities, In this paper, we show that MutY can be trapped in a stable covalent enzyme-DNA intermediate in the presence of sodium borohydride, a new finding that supports the grouping of MutY in that class of DNA glycosylases that possess concomitant apurinic/apyrimidinic lyase activity. To potentially help determine the substrate recognition site of MutY, mutant proteins were constructed. MutY proteins with a Gly116 --> Ala (G116A) or Asp (G116D)mutation had reduced binding affinities for both A/G- and A/GO-containing DNA substrates. The catalytic parameters, however, were differentially affected. While A/G- and A/GO containing DNA were cleaved by MutY with specificity constants (k(cat)/K-m) of 10 and 3.3 min(-1) mu M(-1), respectively, MutY(G116D) cleaved these DNAs 2,300- and 9-fold less efficiently. The catalytic activities of MutY(G116A) with A/G- and A/GO-containing DNA were about the same as that of wild-type MutY. BothMutY(G116A) and MutY(G116D) could be trapped in covalent intermediates with A/GO containing DNA, but with lower efficiencies than the wild type enzyme in the presence of sodium borohydride. MutY(G116A) also formed a covalent intermediate with A/G-containing DNA, but MutY(G116D) did not. Since Gly116 of MutY lies in a region that is highly conserved among several DNA glycosylases, it is likely this conserved region is in the proximity of the substrate binding and/or catalytic sites.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/11/20 alle ore 04:33:36