6B67

Human PP2Calpha (PPM1A) complexed with cyclic peptide c(MpSIpYVA)

6B67 の概要

• エントリーDOI: 10.2210/pdb6b67/pdb
• 分子名称: Protein phosphatase 1A, cyclic peptide c(MpSIpYVA), CALCIUM ION, ... (4 entities in total)
• 機能のキーワード: phosphatase, hydrolase
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 101947.46

構造登録者

Dyda, F.,Kosek, D. (登録日: 2017-10-01, 公開日: 2018-04-11, 最終更新日: 2023-11-15)

主引用文献

Debnath, S.,Kosek, D.,Tagad, H.D.,Durell, S.R.,Appella, D.H.,Acevedo, R.,Grishaev, A.,Dyda, F.,Appella, E.,Mazur, S.J.
A trapped human PPM1A-phosphopeptide complex reveals structural features critical for regulation of PPM protein phosphatase activity.
J. Biol. Chem., 293:7993-8008, 2018

PubMed Abstract: Metal-dependent protein phosphatases (PPM) are evolutionarily unrelated to other serine/threonine protein phosphatases and are characterized by their requirement for supplementation with millimolar concentrations of Mg or Mn ions for activity The crystal structure of human PPM1A (also known as PP2Cα), the first PPM structure determined, displays two tightly bound Mn ions in the active site and a small subdomain, termed the Flap, located adjacent to the active site. Some recent crystal structures of bacterial or plant PPM phosphatases have disclosed two tightly bound metal ions and an additional third metal ion in the active site. Here, the crystal structure of the catalytic domain of human PPM1A, PPM1A, complexed with a cyclic phosphopeptide, c(MpSIpYVA), a cyclized variant of the activation loop of p38 MAPK (a physiological substrate of PPM1A), revealed three metal ions in the active site. The PPM1A D146E-c(MpSIpYVA) complex confirmed the presence of the anticipated third metal ion in the active site of metazoan PPM phosphatases. Biophysical and computational methods suggested that complex formation results in a slightly more compact solution conformation through reduced conformational flexibility of the Flap subdomain. We also observed that the position of the substrate in the active site allows solvent access to the labile third metal-binding site. Enzyme kinetics of PPM1A toward a phosphopeptide substrate supported a random-order, bi-substrate mechanism, with substantial interaction between the bound substrate and the labile metal ion. This work illuminates the structural and thermodynamic basis of an innate mechanism regulating the activity of PPM phosphatases.

PubMed: 29602904
DOI: 10.1074/jbc.RA117.001213

実験手法

X-RAY DIFFRACTION (2.2 Å)