The electrostatic core of the outer membrane protein X from E. coli

Biochim Biophys Acta Biomembr. 2020 Jan 1;1862(1):183031. doi: 10.1016/j.bbamem.2019.183031. Epub 2019 Jul 30.

Abstract

Electrostatic side chain contacts can contribute substantial interaction energy terms to the stability of proteins. The impact of electrostatic interactions on the structure and architecture of outer membrane proteins is however not well studied compared to soluble proteins. Here, we report the results of a systematic study of all charged side chains of the E. coli outer membrane protein X (OmpX). The data identify three distinct salt-bridge clusters in the core of OmpX that contribute significantly to protein stability in dodecylphosphocholine detergent micelles. The three clusters form an "electrostatic core" of the membrane protein OmpX, corresponding in its architectural role to the hydrophobic core of soluble proteins. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.

Keywords: Coulomb interactions; Membrane protein folding; Protein stability; SDS-PAGE; Salt-bridge cluster; Thermal unfolding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry*
  • Bacterial Outer Membrane Proteins / physiology
  • Escherichia coli / chemistry*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / physiology
  • Hydrolases / chemistry*
  • Hydrolases / physiology
  • Hydrophobic and Hydrophilic Interactions
  • Micelles
  • Models, Molecular
  • Protein Conformation
  • Protein Stability
  • Protein Structure, Quaternary
  • Static Electricity*

Substances

  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • Micelles
  • OmpX protein, E coli
  • Hydrolases