3PV2

Structure of Legionella fallonii DegQ (wt)

3PV2 の概要

• エントリーDOI: 10.2210/pdb3pv2/pdb
• 分子名称: DegQ (2 entities in total)
• 機能のキーワード: trypsin fold, pdz domain, chaperone protease, hydrolase
• 由来する生物種: Legionella fallonii
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 192130.55

構造登録者

Wrase, R.,Scott, H.,Hilgenfeld, R.,Hansen, G. (登録日: 2010-12-06, 公開日: 2011-06-15, 最終更新日: 2023-09-06)

主引用文献

Wrase, R.,Scott, H.,Hilgenfeld, R.,Hansen, G.
The Legionella HtrA homologue DegQ is a self-compartmentizing protease that forms large 12-meric assemblies.
Proc.Natl.Acad.Sci.USA, 108:10490-10495, 2011

PubMed Abstract: Proteases of the HtrA family are key factors dealing with folding stress in the periplasmatic compartment of prokaryotes. In Escherichia coli, the well-characterized HtrA family members DegS and DegP counteract the accumulation of unfolded outer-membrane proteins under stress conditions. Whereas DegS serves as a folding-stress sensor, DegP is a chaperone-protease facilitating refolding or degradation of defective outer-membrane proteins. Here, we report the 2.15-Å-resolution crystal structure of the second major chaperone-protease of the periplasm, DegQ from Legionella fallonii. DegQ assembles into large, cage-like 12-mers that form independently of unfolded substrate proteins. We provide evidence that 12-mer formation is essential for the degradation of substrate proteins but not for the chaperone activity of DegQ. In the current model for the regulation of periplasmatic chaperone-proteases, 6-meric assemblies represent important protease-resting states. However, DegQ is unable to form such 6-mers, suggesting divergent regulatory mechanisms for DegQ and DegP. To understand how the protease activity of DegQ is controlled, we probed its functional properties employing designed protein variants. Combining crystallographic, biochemical, and mutagenic data, we present a mechanistic model that suggests how protease activity of DegQ 12-mers is intrinsically regulated and how deleterious proteolysis by free DegQ 3-mers is prevented. Our study sheds light on a previously uncharacterized component of the prokaryotic stress-response system with implications for other members of the HtrA family.

PubMed: 21670246
DOI: 10.1073/pnas.1101084108

実験手法

X-RAY DIFFRACTION (2.15 Å)