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Evolution in action: N and C termini of subunits in related T = 4 viruses exchange roles as molecular switches.

ABSTRACT: The T = 4 tetravirus and T = 3 nodavirus capsid proteins undergo closely similar autoproteolysis to produce the N-terminal beta and C-terminal, lipophilic gamma polypeptides. The gamma peptides and the N termini of beta also act as molecular switches that determine their quasi equivalent capsid structures. The crystal structure of Providence virus (PrV), only the second of a tetravirus (the first was NomegaV), reveals conserved folds and cleavage sites, but the protein termini have completely different structures and the opposite functions of those in NomegaV. N termini of beta form the molecular switch in PrV, whereas gamma peptides play this role in NomegaV. PrV gamma peptides instead interact with packaged RNA at the particle two-folds by using a repeating sequence pattern found in only four other RNA- or membrane-binding proteins. The disposition of peptide termini in PrV is closely related to those in nodaviruses, suggesting that PrV may be closer to the primordial T = 4 particle than NomegaV.

SUBMITTER: Speir JA

PROVIDER: S-EPMC2913159 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

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Evolution in action: N and C termini of subunits in related T = 4 viruses exchange roles as molecular switches.

Speir Jeffrey A JA Taylor Derek J DJ Natarajan Padmaja P Pringle Fiona M FM Ball L Andrew LA Johnson John E JE

Structure (London, England : 1993) 20100601 6

The T = 4 tetravirus and T = 3 nodavirus capsid proteins undergo closely similar autoproteolysis to produce the N-terminal beta and C-terminal, lipophilic gamma polypeptides. The gamma peptides and the N termini of beta also act as molecular switches that determine their quasi equivalent capsid structures. The crystal structure of Providence virus (PrV), only the second of a tetravirus (the first was NomegaV), reveals conserved folds and cleavage sites, but the protein termini have completely di ...[more]

PMID: 20541507

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Evolution in action: N and C termini of subunits in related T = 4 viruses exchange roles as molecular switches.

Publications

Evolution in action: N and C termini of subunits in related T = 4 viruses exchange roles as molecular switches.

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