Conformational switch-defective ΦX174 internal scaffolding proteins kinetically trap assembly intermediates before procapsid formation

Emile B. Gordon, Christopher J. Knuff, Bentley A Fane

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Conformational switching is an overarching paradigm in which to describe scaffolding protein-mediated virus assembly. However, rapid morphogenesis with small assembly subunits hinders the isolation of early morphogenetic intermediates in most model systems. Consequently, conformational switches are often defined by comparing the structures of virions, procapsids and aberrantly assembled particles. In contrast, øX174 morphogenesis proceeds through at least three preprocapsid intermediates, which can be biochemically isolated. This affords a detailed analysis of early morphogenesis and internal scaffolding protein function. Amino acid substitutions were generated for the six C-terminal, aromatic amino acids that mediate most coat-internal scaffolding protein contacts. The biochemical characterization of mutant assembly pathways revealed two classes of molecular defects, protein binding and conformational switching, a novel phenotype. The conformational switch mutations kinetically trapped assembly intermediates before procapsid formation. Although mutations trapped different particles, they shared common second-site suppressors located in the viral coat protein. This suggests a fluid assembly pathway, one in which the scaffolding protein induces a single, coat protein conformational switch and not a series of sequential reactions. In this model, an incomplete or improper switch would kinetically trap intermediates.

Original languageEnglish (US)
Pages (from-to)9911-9918
Number of pages8
JournalJournal of Virology
Volume86
Issue number18
DOIs
StatePublished - Sep 2012

Fingerprint

scaffolding proteins
traps
Morphogenesis
morphogenesis
Capsid Proteins
coat proteins
Proteins
mutation
Virus Assembly
Aromatic Amino Acids
Mutation
viral proteins
protein binding
amino acid substitution
Amino Acid Substitution
virion
Protein Binding
Virion
aromatic compounds
Phenotype

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

Conformational switch-defective ΦX174 internal scaffolding proteins kinetically trap assembly intermediates before procapsid formation. / Gordon, Emile B.; Knuff, Christopher J.; Fane, Bentley A.

In: Journal of Virology, Vol. 86, No. 18, 09.2012, p. 9911-9918.

Research output: Contribution to journalArticle

@article{f26c27a5d30341278de56b6cbbf97ab5,
title = "Conformational switch-defective ΦX174 internal scaffolding proteins kinetically trap assembly intermediates before procapsid formation",
abstract = "Conformational switching is an overarching paradigm in which to describe scaffolding protein-mediated virus assembly. However, rapid morphogenesis with small assembly subunits hinders the isolation of early morphogenetic intermediates in most model systems. Consequently, conformational switches are often defined by comparing the structures of virions, procapsids and aberrantly assembled particles. In contrast, {\o}X174 morphogenesis proceeds through at least three preprocapsid intermediates, which can be biochemically isolated. This affords a detailed analysis of early morphogenesis and internal scaffolding protein function. Amino acid substitutions were generated for the six C-terminal, aromatic amino acids that mediate most coat-internal scaffolding protein contacts. The biochemical characterization of mutant assembly pathways revealed two classes of molecular defects, protein binding and conformational switching, a novel phenotype. The conformational switch mutations kinetically trapped assembly intermediates before procapsid formation. Although mutations trapped different particles, they shared common second-site suppressors located in the viral coat protein. This suggests a fluid assembly pathway, one in which the scaffolding protein induces a single, coat protein conformational switch and not a series of sequential reactions. In this model, an incomplete or improper switch would kinetically trap intermediates.",
author = "Gordon, {Emile B.} and Knuff, {Christopher J.} and Fane, {Bentley A}",
year = "2012",
month = "9",
doi = "10.1128/JVI.01120-12",
language = "English (US)",
volume = "86",
pages = "9911--9918",
journal = "Journal of Virology",
issn = "0022-538X",
publisher = "American Society for Microbiology",
number = "18",

}

TY - JOUR

T1 - Conformational switch-defective ΦX174 internal scaffolding proteins kinetically trap assembly intermediates before procapsid formation

AU - Gordon, Emile B.

AU - Knuff, Christopher J.

AU - Fane, Bentley A

PY - 2012/9

Y1 - 2012/9

N2 - Conformational switching is an overarching paradigm in which to describe scaffolding protein-mediated virus assembly. However, rapid morphogenesis with small assembly subunits hinders the isolation of early morphogenetic intermediates in most model systems. Consequently, conformational switches are often defined by comparing the structures of virions, procapsids and aberrantly assembled particles. In contrast, øX174 morphogenesis proceeds through at least three preprocapsid intermediates, which can be biochemically isolated. This affords a detailed analysis of early morphogenesis and internal scaffolding protein function. Amino acid substitutions were generated for the six C-terminal, aromatic amino acids that mediate most coat-internal scaffolding protein contacts. The biochemical characterization of mutant assembly pathways revealed two classes of molecular defects, protein binding and conformational switching, a novel phenotype. The conformational switch mutations kinetically trapped assembly intermediates before procapsid formation. Although mutations trapped different particles, they shared common second-site suppressors located in the viral coat protein. This suggests a fluid assembly pathway, one in which the scaffolding protein induces a single, coat protein conformational switch and not a series of sequential reactions. In this model, an incomplete or improper switch would kinetically trap intermediates.

AB - Conformational switching is an overarching paradigm in which to describe scaffolding protein-mediated virus assembly. However, rapid morphogenesis with small assembly subunits hinders the isolation of early morphogenetic intermediates in most model systems. Consequently, conformational switches are often defined by comparing the structures of virions, procapsids and aberrantly assembled particles. In contrast, øX174 morphogenesis proceeds through at least three preprocapsid intermediates, which can be biochemically isolated. This affords a detailed analysis of early morphogenesis and internal scaffolding protein function. Amino acid substitutions were generated for the six C-terminal, aromatic amino acids that mediate most coat-internal scaffolding protein contacts. The biochemical characterization of mutant assembly pathways revealed two classes of molecular defects, protein binding and conformational switching, a novel phenotype. The conformational switch mutations kinetically trapped assembly intermediates before procapsid formation. Although mutations trapped different particles, they shared common second-site suppressors located in the viral coat protein. This suggests a fluid assembly pathway, one in which the scaffolding protein induces a single, coat protein conformational switch and not a series of sequential reactions. In this model, an incomplete or improper switch would kinetically trap intermediates.

UR - http://www.scopus.com/inward/record.url?scp=84866177951&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84866177951&partnerID=8YFLogxK

U2 - 10.1128/JVI.01120-12

DO - 10.1128/JVI.01120-12

M3 - Article

C2 - 22761377

AN - SCOPUS:84866177951

VL - 86

SP - 9911

EP - 9918

JO - Journal of Virology

JF - Journal of Virology

SN - 0022-538X

IS - 18

ER -