3LH1

Q191A mutant of the DegS-deltaPDZ

3LH1 の概要

• エントリーDOI: 10.2210/pdb3lh1/pdb
• 関連するPDBエントリー: 3b8j 3lgi 3lgt 3LGu 3lgv 3LGw 3Lgy 3LH3
• 分子名称: Protease degS (2 entities in total)
• 機能のキーワード: protease, stress-sensor, htra, pdz omp, hydrolase, serine protease
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cell inner membrane ; Single-pass membrane protein : P0AEE3
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 25833.13

構造登録者

Sohn, J.,Grant, R.A.,Sauer, R.T. (登録日: 2010-01-21, 公開日: 2010-08-25, 最終更新日: 2024-02-21)

主引用文献

Sohn, J.,Grant, R.A.,Sauer, R.T.
Allostery is an intrinsic property of the protease domain of DegS: implications for enzyme function and evolution.
J.Biol.Chem., 285:34039-34047, 2010

PubMed Abstract: DegS is a periplasmic Escherichia coli protease, which functions as a trimer to catalyze the initial rate-limiting step in a proteolytic cascade that ultimately activates transcription of stress response genes in the cytoplasm. Each DegS subunit consists of a protease domain and a PDZ domain. During protein folding stress, DegS is allosterically activated by peptides exposed in misfolded outer membrane porins, which bind to the PDZ domain and stabilize the active protease. It is not known whether allostery is conferred by the PDZ domains or is an intrinsic feature of the trimeric protease domain. Here, we demonstrate that free DegS(ΔPDZ) equilibrates between active and inactive trimers with the latter species predominating. Substrate binding stabilizes active DegS(ΔPDZ) in a positively cooperative fashion. Mutations can also stabilize active DegS(ΔPDZ) and produce an enzyme that displays hyperbolic kinetics and degrades substrate with a maximal velocity within error of that for fully activated, intact DegS. Crystal structures of multiple DegS(ΔPDZ) variants, in functional and non-functional conformations, support a two-state model in which allosteric switching is mediated by changes in specific elements of tertiary structure in the context of an invariant trimeric base. Overall, our results indicate that protein substrates must bind sufficiently tightly and specifically to the functional conformation of DegS(ΔPDZ) to assist their own degradation. Thus, substrate binding alone may have regulated the activities of ancestral DegS trimers with subsequent fusion of the protease domain to a PDZ domain, resulting in ligand-mediated regulation.

PubMed: 20739286
DOI: 10.1074/jbc.M110.135541

実験手法

X-RAY DIFFRACTION (2.507 Å)