ジャーナル: J Struct Biol / 年: 2012 タイトル: Structure and size determination of bacteriophage P2 and P4 procapsids: function of size responsiveness mutations. 著者: Altaira D Dearborn / Pasi Laurinmaki / Preethi Chandramouli / Cynthia M Rodenburg / Sifang Wang / Sarah J Butcher / Terje Dokland / 要旨: Bacteriophage P4 is dependent on structural proteins supplied by a helper phage, P2, to assemble infectious virions. Bacteriophage P2 normally forms an icosahedral capsid with T=7 symmetry from the ...Bacteriophage P4 is dependent on structural proteins supplied by a helper phage, P2, to assemble infectious virions. Bacteriophage P2 normally forms an icosahedral capsid with T=7 symmetry from the gpN capsid protein, the gpO scaffolding protein and the gpQ portal protein. In the presence of P4, however, the same structural proteins are assembled into a smaller capsid with T=4 symmetry. This size determination is effected by the P4-encoded protein Sid, which forms an external scaffold around the small P4 procapsids. Size responsiveness (sir) mutants in gpN fail to assemble small capsids even in the presence of Sid. We have produced large and small procapsids by co-expression of gpN with gpO and Sid, respectively, and applied cryo-electron microscopy and three-dimensional reconstruction methods to visualize these procapsids. gpN has an HK97-like fold and interacts with Sid in an exposed loop where the sir mutations are clustered. The T=7 lattice of P2 has dextro handedness, unlike the laevo lattices of other phages with this fold observed so far.
名称: Bacteriophage P2 procapsid / タイプ: sample / ID: 1000 / 詳細: gpO is disordered and not visible in the map / 集合状態: 420 copies of gpN and 100-150 copies of gpO / Number unique components: 2
分子量
理論値: 16.884 MDa
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分子 #1: gpN
分子
名称: gpN / タイプ: protein_or_peptide / ID: 1 / Name.synonym: N*, major capsid protein / 集合状態: icosahedral / 組換発現: Yes