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1j5o
From Proteopedia
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| , resolution 3.5Å | |||||||
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| Ligands: | , , , | ||||||
| Activity: | RNA-directed DNA polymerase, with EC number 2.7.7.49 | ||||||
| Related: | 1QE1, 2HMI
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF MET184ILE MUTANT OF HIV-1 REVERSE TRANSCRIPTASE IN COMPLEX WITH DOUBLE STRANDED DNA TEMPLATE-PRIMER
Overview
An important component of triple-drug anti-AIDS therapy is 2', 3'-dideoxy-3'-thiacytidine (3TC, lamivudine). Single mutations at residue 184 of the reverse transcriptase (RT) in HIV cause high-level resistance to 3TC and contribute to the failure of anti-AIDS combination therapy. We have determined crystal structures of the 3TC-resistant mutant HIV-1 RT (M184I) in both the presence and absence of a DNA/DNA template-primer. In the absence of a DNA substrate, the wild-type and mutant structures are very similar. However, comparison of crystal structures of M184I mutant and wild-type HIV-1 RT with and without DNA reveals repositioning of the template-primer in the M184I/DNA binary complex and other smaller changes in residues in the dNTP-binding site. On the basis of these structural results, we developed a model that explains the ability of the 3TC-resistant mutant M184I to incorporate dNTPs but not the nucleotide analog 3TCTP. In this model, steric hindrance is expected for NRTIs with beta- or L- ring configurations, as with the enantiomer of 3TC that is used in therapy. Steric conflict between the oxathiolane ring of 3TCTP and the side chain of beta-branched amino acids (Val, Ile, Thr) at position 184 perturbs inhibitor binding, leading to a reduction in incorporation of the analog. The model can also explain the 3TC resistance of analogous hepatitis B polymerase mutants. Repositioning of the template-primer as observed in the binary complex (M184I/DNA) may also occur in the catalytic ternary complex (M184I/DNA/3TCTP) and contribute to 3TC resistance by interfering with the formation of a catalytically competent closed complex.
About this Structure
1J5O is a Protein complex structure of sequences from Human immunodeficiency virus 1 and Mus musculus. This structure supersedes the now removed PDB entry 1C9R. Full crystallographic information is available from OCA.
Reference
Lamivudine (3TC) resistance in HIV-1 reverse transcriptase involves steric hindrance with beta-branched amino acids., Sarafianos SG, Das K, Clark AD Jr, Ding J, Boyer PL, Hughes SH, Arnold E, Proc Natl Acad Sci U S A. 1999 Aug 31;96(18):10027-32. PMID:10468556
Page seeded by OCA on Sun Mar 30 21:29:09 2008
