2xvr
Phage T7 empty mature head shellPhage T7 empty mature head shell
Structural highlights
FunctionCAPSA_BPT7 Assembles with the minor capsid protein to form an icosahedral capsid with a T=7 symmetry, about 60 nm in diameter, and consisting of 415 capsid proteins. The major and minor capsid proteins are incorporated into the capsid in about a 90/10 ratio respectively. Once the capsid is formed, encapsidates one single copy of the viral genome.[1] Publication Abstract from PubMedMaturation of dsDNA bacteriophages involves assembling the virus prohead from a limited set of structural components, followed by rearrangements required for the stability that is necessary for infecting a host under challenging environmental conditions. Here, we determine the mature capsid structure of T7 at 1 nm resolution by cryo electron microscopy, and compare it with the prohead to reveal the molecular basis of T7 shell maturation. The mature capsid presents an expanded and thinner shell, with a drastic rearrangement of the major protein monomers that increases in their interacting surfaces, in turn resulting in a new bonding lattice. The rearrangements include tilting, in-plane rotation and radial expansion of the subunits, as well as a relative bending of the A and P-domains of each subunit. The unique features of this shell transformation, which does not employ the accessory proteins, inserted domains, or molecular interactions observed in other phages, suggest a simple capsid assembling strategy that may have appeared early in the evolution of these viruses. Molecular rearrangements involved in the capsid shell maturation of bacteriophage T7.,Ionel A, Velazquez-Muriel JA, Luque D, Cuervo A, Caston JR, Valpuesta JM, Martin-Benito J, Carrascosa JL J Biol Chem. 2010 Oct 20. PMID:20962334[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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