Genetic analyses of putative conformation switching and cross-species inhibitory domains in Microviridae external scaffolding proteins

April D. Burch, Bentley A. Fane

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Putative conformational switching and inhibitory regions in the Microviridae external scaffolding protein were investigated. Substitutions for glycine 61, hypothesized to promote a postdimerization conformational switch, have dominant lethal phenotypes. In previous studies, chimeric α3/φX174 proteins for structures α-helix 1 and loop 6/α-helix 7 inhibited φX174 morphogenesis when expressed from high copy number plasmids. To determine if inhibition was due to overexpression, chimeric genes were constructed into the φX174 genome. In coinfections with wild-type, protein ratios would be 1:1. The helix 1 chimera has a recessive lethal phenotype; thus, overexpression confers inhibition. In single infections, the mutant cannot form procapsids, suggesting that helix 1 mediates the initial recognition of structural proteins. The lethal chimeric helix 7 protein has a dominant phenotype. Alone, the mutant forms defective procapsids, suggesting a later morphogenetic defect. The results of second-site genetic analyses indicate that the capsid-external scaffolding protein interface is larger than revealed in the crystal structure.

Original languageEnglish (US)
Pages (from-to)64-71
Number of pages8
JournalVirology
Volume310
Issue number1
DOIs
StatePublished - May 25 2003

ASJC Scopus subject areas

  • Virology

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