Structural highlights
Function[PPIA_HUMAN] PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. [Q72497_9HIV1] Capsid protein p24 forms the conical core of the virus that encapsulates the genomic RNA-nucleocapsid complex (By similarity). Nucleocapsid protein p7 encapsulates and protects viral dimeric unspliced (genomic) RNA. Binds these RNAs through its zinc fingers (By similarity).[SAAS:SAAS012344_004_011858] 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 PubMedCyclophilins constitute a ubiquitous protein family whose functions include protein folding, transport and signaling. They possess both sequence-specific binding and proline cis-trans isomerase activities, as exemplified by the interaction between cyclophilin A (CypA) and the HIV-1 CA protein. Here, we report crystal structures of CypA in complex with HIV-1 CA protein variants that bind preferentially with the substrate proline residue in either the cis or the trans conformation. Cis- and trans-Pro substrates are accommodated within the enzyme active site by rearrangement of their N-terminal residues and with minimal distortions in the path of the main chain. CypA Arg55 guanidinium group probably facilitates catalysis by anchoring the substrate proline oxygen and stabilizing sp3 hybridization of the proline nitrogen in the transition state. Structural insights into the catalytic mechanism of cyclophilin A.,Howard BR, Vajdos FF, Li S, Sundquist WI, Hill CP Nat Struct Biol. 2003 Jun;10(6):475-81. PMID:12730686[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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