1jkh

File:1jkh.gif

spinqualitylabelsall models 1jkh, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF Y181C MUTANT HIV-1 REVERSE TRANSCRIPTASE IN COMPLEX WITH DMP-266(EFAVIRENZ)

OverviewOverview

Mutations at either Tyr181 or Tyr188 within HIV-1 reverse transcriptase, (RT) give high level resistance to many first generation non-nucleoside, inhibitors (NNRTIs) such as the anti-AIDS drug nevirapine. By comparison, second generation inhibitors, for instance the drug efavirenz, show much, greater resilience to these mutations. In order to understand the, structural basis for these differences we have determined a series of, seven crystal structures of mutant RTs in complexes with first and second, generation NNRTIs as well as one example of an unliganded mutant RT. These, are Tyr181Cys RT (TNK-651) to 2.4 A, Tyr181Cys RT (efavirenz) to 2.6 A, Tyr181Cys RT (nevirapine) to 3.0 A, Tyr181Cys RT (PETT-2) to 3.0 A, Tyr188Cys RT (nevirapine) to 2.6 A, Tyr188Cys RT (UC-781) to 2.6 A and, Tyr188Cys RT (unliganded) to 2.8 A resolution. In the two previously, published structures of HIV-1 reverse transcriptase with mutations at 181, or 188 no side-chain electron density was observed within the p66 subunit, (which contains the inhibitor binding pocket) for the mutated residues. In, contrast the mutated side-chains can be seen in the NNRTI pocket for all, seven structures reported here, eliminating the possibility that, disordering contributes to the mechanism of resistance. In the case of the, second generation compounds efavirenz with Tyr181Cys RT and UC-781 with, Tyr188Cys RT there are only small rearrangements of either inhibitor, within the binding site compared to wild-type RT and also for the first, generation compounds TNK-651, PETT-2 and nevirapine with Tyr181Cys RT. For, nevirapine with the Tyr188Cys RT there is however a more substantial, movement of the drug molecule. We conclude that protein conformational, changes and rearrangements of drug molecules within the mutated sites are, not general features of these particular inhibitor/mutant combinations., The main contribution to drug resistance for Tyr181Cys and Tyr188Cys RT, mutations is the loss of aromatic ring stacking interactions for first, generation compounds, providing a simple explanation for the resilience of, second generation NNRTIs, as such interactions make much less significant, contribution to their binding.

About this StructureAbout this Structure

1JKH is a Protein complex structure of sequences from Human immunodeficiency virus type 1 (isolate hxb2) with EFZ as ligand. Active as RNA-directed DNA polymerase, with EC number 2.7.7.49 Full crystallographic information is available from OCA.

ReferenceReference

Structural mechanisms of drug resistance for mutations at codons 181 and 188 in HIV-1 reverse transcriptase and the improved resilience of second generation non-nucleoside inhibitors., Ren J, Nichols C, Bird L, Chamberlain P, Weaver K, Short S, Stuart DI, Stammers DK, J Mol Biol. 2001 Sep 28;312(4):795-805. PMID:11575933

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