A Role for dNTP Binding of Human Immunodeficiency Virus Type 1 Reverse Transcriptase in Viral Mutagenesis†

Biochemistry ◽  
2004 ◽  
Vol 43 (15) ◽  
pp. 4490-4500 ◽  
Author(s):  
Kellie K. Weiss ◽  
Renxiang Chen ◽  
Mark Skasko ◽  
Holly M. Reynolds ◽  
Kwi Lee ◽  
...  
2004 ◽  
Vol 78 (7) ◽  
pp. 3387-3397 ◽  
Author(s):  
Elena N. Peletskaya ◽  
Alex A. Kogon ◽  
Steven Tuske ◽  
Edward Arnold ◽  
Stephen H. Hughes

ABSTRACT Site-directed photoaffinity cross-linking experiments were performed by using human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) mutants with unique cysteine residues at several positions (i.e., positions 65, 67, 70, and 74) in the fingers subdomain of the p66 subunit. Since neither the introduction of the unique cysteine residues into the fingers nor the modification of the SH groups of these residues with photoaffinity cross-linking reagents caused a significant decrease in the enzymatic activities of RT, we were able to use this system to measure distances between specific positions in the fingers domain of RT and double-stranded DNA. HIV-1 RT is quite flexible. There are conformational changes associated with binding of the normal substrates and nonnucleoside RT inhibitors (NNRTIs). Cross-linking was used to monitor intramolecular movements associated with binding of an NNRTI either in the presence or in the absence of an incoming deoxynucleoside triphosphate (dNTP). Binding an incoming dNTP at the polymerase active site decreased the efficiency of cross-linking but caused only modest changes in the preferred positions of cross-linking. This finding suggests that the fingers of p66 are closer to an extended template in the “open” configuration of the enzyme with the fingers away from the active site than in the closed configuration with the fingers in direct contact with the incoming dNTP. NNRTI binding caused increased cross-linking in experiments with diazirine reagents (especially with a diazirine reagent with a longer linker) and a moderate shift in the preferred sites of interaction with the template. Cross-linking occurred closer to the polymerase active site for RTs modified at positions 70 and 74. The effects of NNRTI binding were more pronounced in the absence of a bound dNTP; pretreatment of HIV-1 RT with an NNRTI reduced the effect of dNTP binding. These observations can be explained if the binding of NNRTI causes a decrease in the flexibility in the fingers subdomain of RT-NNRTI complex and a decrease in the distance from the fingers to the template extension.


1999 ◽  
Vol 290 (3) ◽  
pp. 615-625 ◽  
Author(s):  
Mónica Gutiérrez-Rivas ◽  
Ángela Ibáñez ◽  
Miguel A Martı́nez ◽  
Esteban Domingo ◽  
Luis Menéndez-Arias

2006 ◽  
Vol 50 (8) ◽  
pp. 2772-2781 ◽  
Author(s):  
Zhijun Zhang ◽  
Michelle Walker ◽  
Wen Xu ◽  
Jae Hoon Shim ◽  
Jean-Luc Girardet ◽  
...  

ABSTRACT Mutations in and around the catalytic site of the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) are associated with resistance to nucleoside RT inhibitors (NRTIs), whereas changes in the hydrophobic pocket of the RT are attributed to nonnucleoside RT inhibitor (NNRTI) resistance. In this study, we report a novel series of nonnucleoside inhibitors of HIV-1, exemplified by VRX-329747 and VRX-413638, which inhibit both NNRTI- and NRTI-resistant HIV-1 isolates. Enzymatic studies indicated that these compounds are HIV-1 RT inhibitors. Surprisingly, however, following prolonged (6 months) tissue culture selection, this series of nonnucleoside inhibitors did not select NNRTI-resistant mutations in HIV-1 RT. Rather, four mutations (M41L, A62T/V, V118I, and M184V) known to cause resistance to NRTIs and two additional novel mutations (S68N and G112S) adjacent to the catalytic site of the enzyme were selected. Although the M184V mutation appears to be the initial mutation to establish resistance, this mutation alone confers only a two- to fourfold decrease in susceptibility to VRX-329747 and VRX-413638. At least two additional mutations must accumulate for significant resistance. Moreover, while VRX-329747-selected viruses are resistant to lamivudine and emtricitabine due to the M184V mutation, they remain susceptible to zidovudine, stavudine, dideoxyinosine, abacavir, tenofovir, and efavirenz. These results directly demonstrate that VRX-329747 and VRX-413638 are novel nonnucleoside inhibitors of HIV-1 RT with the potential to augment current therapies.


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