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PDBsum entry 3jw2
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References listed in PDB file
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Key reference
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Title
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Highly conserved glycine 86 and arginine 87 residues contribute differently to the structure and activity of the mature HIV-1 protease.
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Authors
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R.Ishima,
Q.Gong,
Y.Tie,
I.T.Weber,
J.M.Louis.
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Ref.
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Proteins, 2010,
78,
1015-1025.
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PubMed id
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Abstract
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The structural and functional role of conserved residue G86 in HIV-1 protease
(PR) was investigated by NMR and crystallographic analyses of substitution
mutations of glycine to alanine and serine (PR(G86A) and PR(G86S)). While
PR(G86S) had undetectable catalytic activity, PR(G86A) exhibited approximately
6000-fold lower catalytic activity than PR. (1)H-(15)N NMR correlation spectra
revealed that PR(G86A) and PR(G86S) are dimeric, exhibiting dimer dissociation
constants (K(d)) of approximately 0.5 and approximately 3.2 muM, respectively,
which are significantly lower than that seen for PR with R87K mutation (K(d)
> 1 mM). Thus, the G86 mutants, despite being partially dimeric under the
assay conditions, are defective in catalyzing substrate hydrolysis. NMR spectra
revealed no changes in the chemical shifts even in the presence of excess
substrate, indicating very poor binding of the substrate. Both NMR chemical
shift data and crystal structures of PR(G86A) and PR(G86S) in the presence of
active-site inhibitors indicated high structural similarity to previously
described PR/inhibitor complexes, except for specific perturbations within the
active site loop and around the mutation site. The crystal structures in the
presence of the inhibitor showed that the region around residue 86 was connected
to the active site by a conserved network of hydrogen bonds, and the two regions
moved further apart in the mutants. Overall, in contrast to the role of R87 in
contributing significantly to the dimer stability of PR, G86 is likely to play
an important role in maintaining the correct geometry of the active site loop in
the PR dimer for substrate binding and hydrolysis. Proteins 2010. (c) 2009
Wiley-Liss, Inc.
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