Lactose permease (LacY) (LacY)

Lactose permease (LacY) is a prototypical membrane transport protein from the Major Facilitator Superfamily (MFS) found in Escherichia coli (UniProt P02920). It is responsible for the coupled transport of a proton and a beta-galactoside, such as lactose, across the cytoplasmic membrane into the cell (PubMed 15155443). The protein is composed of 12 transmembrane alpha-helices and functions through an alternating access mechanism where the substrate binding site is exposed to either side of the membrane (PubMed 12893881). Historically referred to as the M protein, LacY has been extensively studied to elucidate the fundamental principles of secondary active transport and protein-ligand interactions (PubMed 24501215). While it is not a conventional target for human clinical drugs, it is a significant target in biochemical research and synthetic biology for engineering metabolic pathways. Inhibitors and substrates like thiodigalactoside (TDG) are frequently used to probe its structural transitions and binding affinity (PubMed 15155443). Its role in bacterial metabolism makes it a potential, though niche, target for antimicrobial strategies aimed at specific metabolic pathways. The protein's ability to transport a variety of galactosides makes it a versatile tool for studying substrate specificity in transporters.

Other names

M proteinLactose-proton symporterGalactoside permeaselacY gene product

Proton-coupled symport of beta-galactosides