期刊
VIROLOGY
卷 384, 期 1, 页码 144-150出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.virol.2008.11.016
关键词
Virus; Structure; Morphogenesis; Capsid; Maturation; Chaperone
类别
资金
- NIH [A1071982]
Bacteriophage P2 encodes a scaffolding protein, gpO, which is required for correct assembly of P2 procapsids from the gpN major capsid protein. The 284 residue gpO protein also acts as a protease, cleaving itself into an N-terminal fragment, O*, that remains in the capsid following maturation. In addition, gpO is presumed to act as the maturation protease for gpN, which is N-terminally processed to N*, accompanied by DNA packaging and capsid expansion. The protease activity of gpO resides in the N-terminal half of the protein. We show that gpO is a classical serine protease, with a catalytic triad comprised of Asp 19, His 48 and Ser 107. The C-terminal 90 amino acids of gpO are required and sufficient for capsid assembly. This fragment contains a predicted alpha-helical segment between residues 197 and 257 and exists as a multimer in solution, suggesting that oligomerization is required for scaffolding activity. Correct assembly requires the C-terminal cysteine residue, which is most likely involved in transient gpN interactions. Our results suggest a model for gpO scaffolding action in which the N-terminal half of gpO binds strongly to gpN, while oligomerization of the C-terminal a-helical domain of gpO and transient interactions between Cys 284 and gpN lead to capsid assembly. (C) 2008 Elsevier Inc. All rights reserved.
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