Characterization of the structure and function of Escherichia coli DegQ as a representative of the DegQ-like proteases of bacterial HtrA family proteins

Xiao Chen Bai, Xi Jiang Pan, Xiao Jing Wang, Yun Ying Ye, Lei Fu Chang, Dong Leng, Jianlin Lei, Sen Fang Sui

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

HtrA family proteins play a central role in protein quality control in the bacterial periplasmic space. DegQ-like proteases, a group of bacterial HtrA proteins, are characterized by a short LA loop as compared with DegP-like proteases, and are found in many bacterial species. As a representative of the DegQ-like proteases, we report that Escherichia coli DegQ exists in vivo primarily as a trimer (substrate-free) or dodecamer (substrate-containing). Biochemical analysis of DegQ dodecamers revealed that the major copurified protein substrate is OmpA. Importantly, wild-type DegQ exhibited a much lower proteolytic activity, and thus higher chaperone-like activity, than DegP. Furthermore, using cryo-electron microscopy we determined high-resolution structures of DegQ 12- and 24-mers in the presence of substrate, thus revealing the structural mechanism by which DegQ moderates its proteolytic activity.

Original languageEnglish (US)
Pages (from-to)1328-1337
Number of pages10
JournalStructure
Volume19
Issue number9
DOIs
StatePublished - Sep 7 2011

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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