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Structure of N170A MVM mutant empty capsid
Structural highlights
FunctionCAPSD_MUMIP 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 receptors. This attachment induces virion internalization predominantly through clathrin-dependent 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 putative nuclear localization signal(s). VP1 N-terminus might serve as a lipolytic enzyme to breach the endosomal membrane during entry into host cell and might contribute to virus transport to the nucleus.[1] Publication Abstract from PubMedRecent studies reveal that the mechanical properties of virus particles may have been shaped by evolution to facilitate virus survival. Manipulation of the mechanical behavior of virus capsids is leading to a better understanding of viral infection, and to the development of virus-based nanoparticles with improved mechanical properties for nanotechnological applications. In the minute virus of mice (MVM), deleterious mutations around capsid pores involved in infection-related translocation events invariably increased local mechanical stiffness and interfered with pore-associated dynamics. To provide atomic-resolution insights into biologically relevant changes in virus capsid mechanics, we have determined by X-ray crystallography the structural effects of deleterious, mechanically stiffening mutations around the capsid pores. Data show that the cavity-creating N170A mutation at the pore wall does not induce any dramatic structural change around the pores, but instead generates subtle rearrangements that propagate throughout the capsid, resulting in a more compact, less flexible structure. Analysis of the spacefilling L172W mutation revealed the same relationship between increased stiffness and compacted capsid structure. Implications for understanding connections between virus mechanics, structure, dynamics and infectivity, and for engineering modified virus-based nanoparticles, are discussed. Structural basis for biologically relevant mechanical stiffening of a virus capsid by cavity-creating or spacefilling mutations.,Guerra P, Valbuena A, Querol-Audi J, Silva C, Castellanos M, Rodriguez-Huete A, Garriga D, Mateu MG, Verdaguer N Sci Rep. 2017 Jun 22;7(1):4101. doi: 10.1038/s41598-017-04345-w. PMID:28642465[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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