Structural highlights
Function[POL_RSVP] Capsid protein p27 forms the spherical core of the virus that encapsulates the genomic RNA-nucleocapsid complex (By similarity). The aspartyl protease mediates proteolytic cleavages of Gag and Gag-Pol polyproteins during or shortly after the release of the virion from the plasma membrane. Cleavages take place as an ordered, step-wise cascade to yield mature proteins. This process is called maturation. Displays maximal activity during the budding process just prior to particle release from the cell (By similarity). 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 PubMedThe Rous sarcoma virus (RSV) protease S9 variant has been engineered to exhibit high affinity for HIV-1 protease substrates and inhibitors in order to verify the residues deduced to be critical for the specificity differences. The variant has 9 substitutions (S38T, I42D, I44V, M73V, A100L, V104T, R105P, G106V, and S107N) of structurally equivalent residues from HIV-1 protease. Unlike the wild-type enzyme, RSV S9 protease hydrolyzes peptides representing the HIV-1 protease polyprotein cleavage sites. The crystal structure of RSV S9 protease with the inhibitor, Arg-Val-Leu-r-Phe-Glu-Ala-Nle-NH2, a reduced peptide analogue of the HIV-1 CA-p2 cleavage site, has been refined to an R factor of 0.175 at 2.4-A resolution. The structure shows flap residues that were not visible in the previous crystal structure of unliganded wild-type enzyme. Flap residues 64-76 are structurally similar to residues 47-59 of HIV-1 protease. However, residues 61-63 form unique loops at the base of the flaps. Mutational analysis indicates that these loop residues are essential for catalytic activity. Side chains of flap residues His 65 and Gln 63' make hydrogen bond interactions with the inhibitor P3 amide and P4' carbonyl oxygen, respectively. Other interactions of RSV S9 protease with the CA-p2 analogue are very similar to those observed in the crystal structure of HIV-1 protease with the same inhibitor. This is the first crystal structure of an avian retroviral protease in complex with an inhibitor, and it verifies our knowledge of the molecular basis for specificity differences between RSV and HIV-1 proteases. Structural basis for specificity of retroviral proteases.,Wu J, Adomat JM, Ridky TW, Louis JM, Leis J, Harrison RW, Weber IT Biochemistry. 1998 Mar 31;37(13):4518-26. PMID:9521772[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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