Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Dynamics of translesion DNA synthesis catalyzed by the bacteriophage T4 exonuclease-deficient DNA polymerase
Autore:
Berdis, AJ;
Indirizzi:
Case Western Reserve Univ, Sch Med, Dept Pharmacol, Cleveland, OH 44106 USA Case Western Reserve Univ Cleveland OH USA 44106 Cleveland, OH 44106 USA
Titolo Testata:
BIOCHEMISTRY
fascicolo: 24, volume: 40, anno: 2001,
pagine: 7180 - 7191
SICI:
0006-2960(20010619)40:24<7180:DOTDSC>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
APURINIC APYRIMIDINIC SITES; REPLICATION FIDELITY; DEOXYRIBONUCLEIC-ACID; HOLOENZYME COMPLEX; KINETIC MECHANISM; MAMMALIAN-CELLS; ABASIC SITE; REPAIR; MUTAGENESIS; INSERTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Berdis, AJ Case Western Reserve Univ, Sch Med, Dept Pharmacol, 10900 Euclid Ave, Cleveland, OH 44106 USA Case Western Reserve Univ 10900 Euclid Ave Cleveland OH USA 44106
Citazione:
A.J. Berdis, "Dynamics of translesion DNA synthesis catalyzed by the bacteriophage T4 exonuclease-deficient DNA polymerase", BIOCHEM, 40(24), 2001, pp. 7180-7191

Abstract

The mechanism and dynamics of translesion DNA synthesis were evaluated using primer/templates containing a tetrahydrofuran moiety designed to mimic an abasic site. Steady-state kinetic analysis reveals that the T4 DNA polymerase preferentially incorporates dATP across from the abasic site with 100-fold higher efficiency than the other nucleoside triphosphates. Under steady-state conditions, the catalytic efficiency of dATP incorporation across from an abasic site is only 220-fold lower than that across from T. Surprisingly, misincorporation across from T is favored 4-6-fold versus replicationacross an abasic site, suggesting that the dynamics of the polymerization cycle are differentially affected by formation of aberrant base pairs as opposed to the lack of base-pairing capabilities afforded by the abasic site. Linear pre-steady-state time courses were obtained for the incorporation of any dNTP across from an abasic site, indicating that chemistry or a step prior to chemistry is rate-limiting for the polymerization cycle. Low elemental effects (<3) measured by substituting the <alpha>-thiotriphosphate analogues for dATP, dCTP, and dGTP indicate that chemistry is not solely rate-limiting. Single-turnover experiments yield k(pol)/K-d values that are essentially identical to k(cat)/K-m values and provide further evidence that the conformational change preceding chemistry is rate-limiting. Extension beyond an A:abasic mispair is approximately 20-fold and 100-fold faster than extension beyond a G:abasic mispair or C:abasic mispair, respectively. Extension from the G:abasic or A:abasic site mispair generates significant elemental effects (between 5 and 20) and suggests that chemistry is at least partially rate-limiting for extension beyond either mispair.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 16:06:25