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Titolo:
DNA DETERMINANTS AND SUBSTRATE SPECIFICITIES OF ESCHERICHIA-COLI MUTY
Autore:
LU AL; TSAIWU JJ; CILLO J;
Indirizzi:
UNIV MARYLAND,SCH MED,DEPT BIOL CHEM BALTIMORE MD 21201
Titolo Testata:
The Journal of biological chemistry
fascicolo: 40, volume: 270, anno: 1995,
pagine: 23582 - 23588
SICI:
0021-9258(1995)270:40<23582:DDASSO>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
MISMATCH REPAIR; BASE-PAIR; IONIZING-RADIATION; RNA-POLYMERASE; GENE-PRODUCT; DAMAGED BASE; GLYCOSYLASE; DUPLEX; SITE; 8-OXOGUANINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
42
Recensione:
Indirizzi per estratti:
Citazione:
A.L. Lu et al., "DNA DETERMINANTS AND SUBSTRATE SPECIFICITIES OF ESCHERICHIA-COLI MUTY", The Journal of biological chemistry, 270(40), 1995, pp. 23582-23588

Abstract

Potential DNA contacts involved in the specific interaction between the Escherichia coli MutY protein and a 40-mer oligonucleotide containing an A/G mismatch have been examined by alkylation interference techniques. Ethylation interference patterns suggest that more than five phosphates are involved in electrostatic interactions between MutY and DNA, Interestingly, MutY has more contacts on the G-strand than on the A strand. Methylation at both the N-7 position of the mismatched G andthe N-3 position of the mispaired A interfere with MutY binding, In addition to these mismatched bases, MutY also contacts purines on both sides of the mismatch. Binding and endonuclease activities of MutY were assayed with 20-mer oligonucleotides containing A/G, A/C, A/7,8-dihydro-8-oxo-guanine (A/GO), A/inosine (A/I), A/2-aminopurine (A/2AP), nebularine/G (N/G), inosine/G (I/G), 2AP/G, and 7-deaza-adenosine/G (Z/G) mispairs, The C-8 keto group of GO in A/GO contributes to a much tighter binding but weaker endonuclease activity than is seen with A/G. Because A/I is not specifically well recognized by MutY, the a-amino group of G in A/G is essential for recognition, The C-6 keto group present in A/G but absent in A/2AP is also important for recognition, The B-amino group of adenine appears not to be required for either binding or endonuclease activity because N/G is as good a substrate as A/G. The 2AP/G mispair is bound and cleaved weaker than is the A/G mispair, Binding and endonuclease activities are abolished when the N-7 group ofA is replaced by C-7 as in the Z/G mispair, When a C-6 keto group is present as in the L/G pair, its binding by MutY is as good as for A/G,but no endonuclease activity is observed, Taken together, our data suggest that DNA sequences proximal to and specific functional groups ofmismatched bases are necessary for recognition and catalysis by MutY protein.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/11/20 alle ore 03:21:18