Homodimerization of the p51 subunit of HIV-1 reverse transcriptase.
Homodimerization of the p51 subunit of HIV-1 reverse transcriptase.
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DOI：
10.1021/bi902116z
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发表时间：
2010-04-06
期刊：
影响因子：
2.9
通讯作者：
London RE
中科院分区：
文献类型：
--
作者：
Zheng X;Mueller GA;Cuneo MJ;Derose EF;London RE
The dimerization of HIV reverse transcriptase (RT), required to obtain the active form of the enzyme, is influenced by mutations, non-nucleoside reverse transcriptase inhibitors (NNRTIs), nucleotide substrates, Mg ions, temperature, and by specifically designed dimerization inhibitors. In the present study, we have utilized NMR spectroscopy of the [methyl-13C] methionine labeled enzyme and small angle X-ray scattering (SAXS) to investigate how several of these factors influence the dimerization behavior of the p51 subunit. The 1H-13C HSQC spectrum of p51 obtained at micromolar concentrations indicates that a significant fraction of the p51 adopts a “p66-like” conformation. SAXS data obtained on p51 samples were used to determine the fractions of monomer and dimer in the sample, and to evaluate the conformation of the fingers/thumb subdomain. All of the p51 monomer observed was found to adopt the compact, “p51C” conformation observed for the p51 subunit in the RT heterodimer. The NMR and SAXS data indicate that the p51 homodimer adopts a structure that is similar to the p66/p51 heterodimer, with one p51C subunit and a second p51 subunit in an extended, “p51E” conformation that resembles the p66 subunit of the heterodimer. The fractional dimer concentration and the fingers/thumb orientation is found to depend strongly on the experimental conditions, and exhibits a qualitative dependence on nevirapine and ionic strength (KCl) that is similar to the behavior reported for the heterodimer and the p66 homodimer. The L289K mutation interferes with p51 homodimer formation as it does with formation of the heterodimer, despite its location far from the dimer interface. This effect is readily interpreted in terms of a conformational selection model, in which p51L289K has a much greater preference for the compact, p51C conformation. Reduced dimer formation then results from the reduced ratio of the p51EL289K to p51CL289K monomers.
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影响因子：
2.9
作者：
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通讯作者：
leGrice, SFJ
影响因子：
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