Hydrogen/Deuterium Exchange - Mass Spectrometry Reveals Conformational Changes between Human Phosphatase PP2Cα and a Catalytically Inactive Metal Binding Site Mutant

摘要

Purpose PP2Cα is a Mg~(2+)/ Mn~(2+)-dependent serine/theronine phosphatase that loses enzymatic activity and the ability to bind a Mg~(2+) ion when the aspartic acid (D) residue at position 146 is mutated to alanine (A). The goal of this work is to study how the D146A mutation affects the global structure of the enzyme. Results Using hydrogen deuterium exchange - mass spectrometry (HDX-MS) we have probed PP2Cα and a mutant lacking the third metal binding site. When the third metal is not bound, the enzyme is more flexible. This work provides new insights in clarifying the catalytic mechanism.