Deciphering a missing piece of the branched-chain amino acids uptake puzzle: YhjE is an L-isoleucine and L-valine transporter in <i>Escherichia coli</i> K-12.

ABSTRACT: Branched-chain amino acid (BCAA) uptake in bacteria underpins fitness, pathogenesis, and industrial strain performance, yet the transport landscape, even in Escherichia coli, remains incomplete. Here, we identify and characterize YhjE as a BCAA permease specific for L-isoleucine and L-valine. Selection for L-valine-resistant clones in a ΔlivKHMGF ΔbrnQ background repeatedly recovered mutations in yhjE, indicating that YhjE mediates L-valine entry. Deletion of yhjE in the ΔlivKHMGF ΔbrnQ background increased the L-isoleucine requirement and raised the minimal inhibitory concentration of L-valine, whereas the L-leucine requirement was unaffected. Direct uptake assays showed that YhjE mediates L-isoleucine and L-valine import. Kinetic analysis yielded appare

SUBMITTER: Molev SV 

PROVIDER: S-EPMC12708883 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature