A pH-independent quiet OmpG pore with enhanced electrostatic repulsion among the extracellular loops.

ABSTRACT: Membrane protein pores have emerged as powerful nanopore sensors for single-molecule detection. OmpG, a monomeric nanopore, is comprised of fourteen β-strands connected by seven flexible extracellular loops. The OmpG nanopore exhibits pH-dependent gating as revealed by planar lipid bilayer studies. Current evidence strongly suggests that the dynamic movement of loop 6 is responsible for the gating mechanism. In this work, we have shown that enhancing the electrostatic repulsion forces between extracellular loops suppressed the pH-dependent gating. Our mutant containing additional negative charges in loop 6 and loop 1 exhibited minimal spontaneous gating and reduced sensitivity to pH changes compared to the wild type OmpG. These results provide new evidence to support the mechanism of OmpG

SUBMITTER: Pham B 

PROVIDER: S-EPMC7704735 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature