Stereo-selectivity of HIV-1 reverse transcriptase toward isomers of thymidine-5'-O-1-thiotriphosphate.
Protein Sci
; 14(7): 1929-33, 2005 Jul.
Article
em En
| MEDLINE
| ID: mdl-15937285
ABSTRACT
The first pre-steady-state kinetic analysis of the stereo-selective incorporation of Rp- and Sp-isomers of thymidine-5'-O-1-thiotriphosphate (TTPalphaS) by HIV-1 reverse transcriptase (RT) is reported. Rates of polymerization (k(pol)), apparent dissociation constants (K(d)), and substrate specificities (k(pol)/K(d)) were measured for TTP, Rp-TTPalphaS, and Sp-TTPalphaS in the presence of Mg(2+), Mn(2+), and Co(2+). HIV-1 RT exhibits a strong preference to incorporate Sp-TTPalphaS over Rp-TTPalphaS in the presence of Mg(2+); however, this stereo-selective preference was decreased when Mg(2+) was replaced with Mn(2+) and Co(2+). Furthermore, HIV-1 RT exhibited no phosphorothioate elemental effects for the incorporation of Sp-TTPalphaS, but large elemental effects were calculated for Rp-TTPalphaS for each of the metals tested. These results are discussed in relation to our current understanding of the RT active-site structure and the mechanism of DNA synthesis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Timidina
/
Transcriptase Reversa do HIV
Limite:
Humans
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article