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Titolo:
Formation of a schiff base intermediate is not required for the adenine glycosylase activity of Escherichia coli MutY
Autore:
Williams, SD; David, SS;
Indirizzi:
Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA Univ Utah Salt Lake City UT USA 84112 Chem, Salt Lake City, UT 84112 USA
Titolo Testata:
BIOCHEMISTRY
fascicolo: 47, volume: 38, anno: 1999,
pagine: 15417 - 15424
SICI:
0006-2960(19991123)38:47<15417:FOASBI>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
MISMATCH REPAIR ENZYME; G-A MISPAIRS; CATALYTIC MECHANISM; DNA GLYCOSYLASE; FPG PROTEIN; ENDONUCLEASE-III; RECOGNITION; MUTATIONS; IDENTIFICATION; SPECIFICITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: David, SS Univ Utah, Dept Chem, 315 S 1400 E, Salt Lake City, UT 84112 USAUniv Utah 315 S 1400 E Salt Lake City UT USA 84112 UT 84112 USA
Citazione:
S.D. Williams e S.S. David, "Formation of a schiff base intermediate is not required for the adenine glycosylase activity of Escherichia coli MutY", BIOCHEM, 38(47), 1999, pp. 15417-15424

Abstract

The mutY gene product of Escherichia coli is a 39-kDa protein that catalyzes the removal of adenine bases mispaired with 2'-deoxyguanosine and 7,8-dihydro-8-oxo-2'-deoxyguanosine (OG) in DNA. Although adenine removal proceeds via monofunctional glycosylase activity, MutY is able to form covalent adducts with substrate DNA in the presence of borohydride, a trait otherwise known to be associated only with enzymes having bifunctional,glycosylase/APlyase activity. To help identify active site residues involved in the formation of MutY-DNA adducts in the presence of borohydride, a series of site-directed mutant forms of MutY were generated. Our data show that Lys 142 isthe primary residue involved in cross-link formation. The absence of Lys 142 results in near elimination of the enzyme-DNA adducts formed relative towild-type, suggesting that this residue is the primary one involved in forming covalent associations with DNA during MutY catalysis, Importantly, theenzymatic activity and DNA binding of the K142A enzyme is nearly identicalto the WT enzyme. This shows that formation of the covalent intermediate is not required for adenine removal by MutY, Furthermore, this suggests thatthe covalent intermediate is formed by reaction of Lys 142 with the OG/G:(AP site) product, and this may be a consequence of MutY's unusually high affinity for the product of its glycosylase action.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 16:07:04