Interaction of intramembrane metalloprotease SpoIVFB with substrate Pro-σK

Proc Natl Acad Sci U S A. 2017 Dec 12;114(50):E10677-E10686. doi: 10.1073/pnas.1711467114. Epub 2017 Nov 27.

Abstract

Intramembrane proteases (IPs) cleave membrane-associated substrates in nearly all organisms and regulate diverse processes. A better understanding of how these enzymes interact with their substrates is necessary for rational design of IP modulators. We show that interaction of Bacillus subtilis IP SpoIVFB with its substrate Pro-σK depends on particular residues in the interdomain linker of SpoIVFB. The linker plus either the N-terminal membrane domain or the C-terminal cystathione-β-synthase (CBS) domain of SpoIVFB was sufficient for the interaction but not for cleavage of Pro-σK Chemical cross-linking and mass spectrometry of purified, inactive SpoIVFB-Pro-σK complex indicated residues of the two proteins in proximity. A structural model of the complex was built via partial homology and by using constraints based on cross-linking data. In the model, the Proregion of Pro-σK loops into the membrane domain of SpoIVFB, and the rest of Pro-σK interacts extensively with the linker and the CBS domain of SpoIVFB. The extensive interaction is proposed to allow coordination between ATP binding by the CBS domain and Pro-σK cleavage by the membrane domain.

Keywords: Bacillus subtilis; SpoIVFB; intramembrane protease; regulated intramembrane proteolysis; sporulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Endopeptidases / chemistry
  • Endopeptidases / genetics
  • Endopeptidases / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Docking Simulation
  • Protein Binding
  • Sigma Factor / chemistry
  • Sigma Factor / genetics
  • Sigma Factor / metabolism*

Substances

  • Bacterial Proteins
  • Membrane Proteins
  • Sigma Factor
  • pro-sigmaK protein, Bacillus subtilis
  • Endopeptidases
  • spoIVFB protein, Bacillus subtilis