2cas | pdb_00002cas
THE CANINE PARVOVIRUS EMPTY CAPSID STRUCTURE
Structural highlights
Function[CAPSD_PAVCB] Capsid protein self-assembles to form an icosahedral capsid with a T=1 symmetry, about 22 nm in diameter, and consisting of 60 copies of two size variants of the capsid proteins, VP1 and VP2, which differ by the presence of an N-terminal extension in the minor protein VP1. The capsid encapsulates the genomic ssDNA. Capsid proteins are responsible for the attachment to host cell receptor TFRC. This attachment induces virion internalization predominantly through clathrin-endocytosis. Binding to the host receptors also induces capsid rearrangements leading to surface exposure of VP1 N-terminus, specifically its phospholipase A2-like region and nuclear localization signal(s). VP1 N-terminus might serve as a lipolytic enzyme to breach the endosomal membrane during entry into host cell. Intracytoplasmic transport involves microtubules and interaction between capsid proteins and host dynein. Exposure of nuclear localization signal probably allows nuclear import of capsids (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 structure of empty canine parvovirus capsids shows that residues 37 to the carboxy-terminal residue 584 (VP2 numbering) are ordered in each of the 60 subunits. The central structural motif of each subunit is the eight-stranded antiparallel beta-barrel that has been found in many other virus structures. Five beta-hairpin turns form a beta-cylindrical structure at each icosahedral 5-fold axis. The N-terminal glycine-rich sequence can be accommodated within this cylinder without excessive steric hindrance, consistent with the electron density distribution. By far the largest conformational differences between the full and empty virus were found in the region where some ordered DNA has been observed to bind in canine parvovirus full particles. Extensive interactions among 3-fold related subunits indicate that a trimeric subunit might be a viral assembly intermediate. The canine parvovirus empty capsid structure.,Wu H, Rossmann MG J Mol Biol. 1993 Sep 20;233(2):231-44. PMID:8377200[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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