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ALTERNATIVE NATIVE FLAP CONFORMATION REVEALED BY 2.3 ANGSTROMS RESOLUTION STRUCTURE OF SIV PROTEINASEALTERNATIVE NATIVE FLAP CONFORMATION REVEALED BY 2.3 ANGSTROMS RESOLUTION STRUCTURE OF SIV PROTEINASE
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedA large conformational change is observed between HIV-1 proteinase in the ligand-free state and in complexes with transition-state inhibitors. Crystal structures of this enzyme have either the flaps open for the native or ligand-free enzyme or the flaps closed for peptidomimetic ligand-bound enzyme. We describe the structure of native recombinant SIV proteinase which like other retroviral proteinases crystallizes as a perfect 2-fold symmetric dimer but in a different crystal packing arrangement. In contrast to HIV-1 PR we show that SIV proteinase in the ligand-free state adopts the closed flaps conformation, demonstrating that ligand binding is not a prerequisite for the closed flaps conformation. The catalytic water was clearly observed between the two aspartates which were not perfectly co-planar, and in this structure the active site cleft is more restricted than for either inhibitor bound or ligand-free HIV-1 proteinase. Accommodation of two bulkier side-chains in the simian enzyme core has resulted in a more exposed N terminus than for HIV-1 PR which we predict could enhance autocatalytic cleavage at the N terminus. Alternative native flap conformation revealed by 2.3 A resolution structure of SIV proteinase.,Wilderspin AF, Sugrue RJ J Mol Biol. 1994 May 27;239(1):97-103. PMID:8196050[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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