Conformational flexibility driving charge-selective substrate translocation across a bacterial transporter.

ABSTRACT: Bacterial membrane porins facilitate the translocation of small molecules while restricting large molecules, and this mechanism remains elusive at the molecular level. Here, we investigate the selective uptake of large cyclic sugars across an unusual passive membrane transporter, CymA, comprising a charged zone and a constricting N terminus segment. Using a combination of electrical recordings, protein mutagenesis and molecular dynamics simulations, we establish substrate translocation across CymA governed by the electrostatic pore properties and conformational dynamics of the constriction segment. Notably, we show that the variation in pH of the environment resulted in reversible modulation of the substrate binding site in the pore, thereby regulating charge-selective transport of cationi

SUBMITTER: Vikraman D 

PROVIDER: S-EPMC11186346 | biostudies-literature | 2024 Jun

REPOSITORIES: biostudies-literature