The closed structure of the MscS mechanosensitive channel. Cross-linking of single cysteine mutants

Samantha Miller, Michelle Diane Edwards, C. Ozdemir, Ian Rylance Booth

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Mechanosensitive channels must make a large conformational change during the transition from the closed to the open state. The crystal structure of the open form of the Escherichia coli MscS channel was recently solved and depicts a homoheptamer (1). In this study, cross-linking of site-specific cysteine substitutions demonstrates that residues up to 10 - 33 Angstrom apart in the crystal structure readily form disulfide bridges in the closed form and can also be cross-linked by a 10-Angstrom linker. Crosslinking between adjacent subunits stabilizes the heptameric form of the channel providing biochemical evidence to support the crystal structure. The data are consistent with the published model ( 1) in that the membrane domain is highly flexible and that the closed to open transition may involve a significant displacement of transmembrane helices 1 and 2, possibly by as much as 30 Angstrom. The data are also consistent with significant flexibility of the cytoplasmic domain.

Original languageEnglish
Pages (from-to)32246-32250
Number of pages4
JournalThe Journal of Biological Chemistry
Volume278
Issue number34
DOIs
Publication statusPublished - Aug 2003

Keywords

  • ESCHERICHIA-COLI MSCS
  • GATING MECHANISM
  • ION-CHANNEL
  • K+ CHANNEL
  • STOICHIOMETRY
  • RECEPTOR
  • DYNAMICS
  • DOMAIN

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