Random mutagenesis of the prokaryotic peptide transporter YdgR identifies potential periplasmic gating residues.

ABSTRACT: The peptide transporter (PTR) family represents a group of proton-coupled secondary transporters responsible for bulk uptake of amino acids in the form of di- and tripeptides, an essential process employed across species ranging from bacteria to humans. To identify amino acids critical for peptide transport in a prokaryotic PTR member, we have screened a library of mutants of the Escherichia coli peptide transporter YdgR using a high-throughput substrate uptake assay. We have identified 35 single point mutations that result in a full or partial loss of transport activity. Additional analysis, including homology modeling based on the crystal structure of the Shewanella oneidensis peptide transporter PepT(so), identifies Glu(56) and Arg(305) as potential periplasmic gating residues. In addit

SUBMITTER: Malle E 

PROVIDER: S-EPMC3123079 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature