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CRYSTAL STRUCTURE OF HUMAN ADENOVIRUS 2 PROTEINASE WITH ITS 11 AMINO ACID COFACTOR AT 1.6 ANGSTROM RESOLUTION
Structural highlights
FunctionPRO_ADE02 Cleaves viral precursor proteins (pTP, pIIIa, pVI, pVII, pVIII, and pX) inside newly assembled particles giving rise to mature virions. Protease complexed to its cofactor slides along the viral DNA to specifically locate and cleave the viral precursors. Mature virions have a weakened organization compared to the unmature virions, thereby facilitating subsequent uncoating. Without maturation, the particle lacks infectivity and is unable to uncoat. Late in adenovirus infection, in the cytoplasm, may participate in the cytoskeleton destruction. Cleaves host cells cytoskeletal keratins K7 and K18.[1] 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 crystal structure of the human adenovirus proteinase (AVP), a cysteine proteinase covalently bound to its 11-amino-acid peptide cofactor pVIc, has been solved to 1.6-A resolution with a crystallographic R-factor of 0.136, R(free)=0.179. The fold of AVP-pVIc is new and the structural basis for it is described in detail. The polypeptide chain of AVP folds into two domains. One domain contains a five-strand beta-sheet with two peripheral alpha-helices; this region represents the hydrophobic core of the protein. A second domain contains the N terminus, several C-terminal alpha-helices, and a small peripheral anti-parallel beta-sheet. The domains interact through an extended polar interface. pVIc spans the two domains like a strap, its C-terminal portion forming a sixth strand on the beta-sheet. The active site is in a long, deep groove located between the two domains. Portions are structurally similar to the active site of the prototypical cysteine proteinase papain, especially some of the Calpha backbone atoms (r.m.s. deviation of 0.354 A for 12 Calpha atoms). The active-site nucleophile of AVP, the conserved Cys(122), was shown to have a pK(a) of 4.5, close to the pK(a) of 3.0 for the nucleophile of papain, suggesting that a similar ion pair arrangement with His(54) may be present in AVP-pVIc. The interactions between AVP and pVIc include 24 non-beta-strand hydrogen bonds, six beta-strand hydrogen bonds and one covalent bond. Of the 204 amino acid residues in AVP, 33 are conserved among the many serotypes of adenovirus, and these aid in forming the active site groove, are involved in substrate specificity or interact between secondary structure elements. Crystallographic structure at 1.6-A resolution of the human adenovirus proteinase in a covalent complex with its 11-amino-acid peptide cofactor: insights on a new fold.,McGrath WJ, Ding J, Didwania A, Sweet RM, Mangel WF Biochim Biophys Acta. 2003 May 30;1648(1-2):1-11. PMID:12758141[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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