1sgu
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Comparing the Accumulation of Active Site and Non-active Site Mutations in the HIV-1 Protease
OverviewOverview
Protease inhibitor resistance still poses one of the greatest challenges, in treating HIV. To better design inhibitors able to target resistant, proteases, a deeper understanding is needed of the effects of accumulating, mutations and the contributions of active- and nonactive-site mutations to, the resistance. We have engineered a series of variants containing the, nonactive-site mutations M46I and I54V and the active-site mutation I84V., These mutations were added to a protease clone (V6) isolated from a, pediatric patient on ritonavir therapy. This variant possessed the, ritonavir-resistance-associated mutations in the active-site (V32I and, V82A) and nonactive-site mutations (K20R, L33F, M36I, L63P, A71V, and, L90M). The I84V mutation had the greatest effect on decreasing catalytic, efficiency, 10-fold when compared to the pretherapy clone LAI. The, decrease in catalytic efficiency was partially recovered by the addition, of mutations M46I and I54V. The M46I and I54V were just as effective at, decreasing inhibitor binding as the I84V mutation when compared to V6 and, LAI. The V6(54/84) variant showed over 1000-fold decrease in, inhibitor-binding strength to ritonavir, indinavir, and nelfinavir when, compared to LAI and V6. Crystal-structure analysis of the V6(54/84), variant bound to ritonavir and indinavir shows structural changes in the, 80's loops and active site, which lead to an enlarged binding cavity when, compared to pretherapy structures in the Protein Data Bank. Structural, changes are also seen in the 10's and 30's loops, which suggest possible, changes in the dynamics of flap opening and closing.
About this StructureAbout this Structure
1SGU is a Single protein structure of sequence from Human immunodeficiency virus 1 with MK1 as ligand. Active as HIV-1 retropepsin, with EC number 3.4.23.16 Full crystallographic information is available from OCA.
ReferenceReference
Comparing the accumulation of active- and nonactive-site mutations in the HIV-1 protease., Clemente JC, Moose RE, Hemrajani R, Whitford LR, Govindasamy L, Reutzel R, McKenna R, Agbandje-McKenna M, Goodenow MM, Dunn BM, Biochemistry. 2004 Sep 28;43(38):12141-51. PMID:15379553
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