1r0a

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spinqualitylabelsall models 1r0a, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of HIV-1 reverse transcriptase covalently tethered to DNA template-primer solved to 2.8 angstroms

Overview

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.

About this Structure

1R0A is a Protein complex structure of sequences from Human immunodeficiency virus 1 and Mus musculus with GLC, MG and GOL as ligands. Active as RNA-directed DNA polymerase, with EC number 2.7.7.49 Full crystallographic information is available from OCA.

Reference

Nonnucleoside inhibitor binding affects the interactions of the fingers subdomain of human immunodeficiency virus type 1 reverse transcriptase with DNA., Peletskaya EN, Kogon AA, Tuske S, Arnold E, Hughes SH, J Virol. 2004 Apr;78(7):3387-97. PMID:15016861

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