title: Characterization of the structure and function of Escherichia coli DegQ as a representative of the DegQ-like proteases of bacterial HtrA family proteins.
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.
authors: State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China.
authors: Xiao-chen
authors: XC
authors: Bai
authors: Xi-jiang
authors: XJ
authors: Pan
authors: Xiao-jing
authors: XJ
authors: Wang
authors: Yun-ying
authors: YY
authors: Ye
authors: Lei-fu
authors: LF
authors: Chang
authors: Dong
authors: D
authors: Leng
authors: Jianlin
authors: J
authors: Lei
authors: Sen-Fang
authors: SF
authors: Sui
mesh_terms: D020134:Catalytic Domain; D002850:Chromatography, Gel; D020285:Cryoelectron Microscopy; D057075:Enzyme Assays; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000648:ultrastructure; D008958:Models, Molecular; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000648:ultrastructure; D013499:Surface Properties
chemical_list: D029968:Escherichia coli Proteins; C098059:DegQ protein, E coli; D012697:Serine Endopeptidases