X-ray crystallography reveals molecular recognition mechanism for sugar binding in a melibiose transporter MelB.

ABSTRACT: Major facilitator superfamily_2 transporters are widely found from bacteria to mammals. The melibiose transporter MelB, which catalyzes melibiose symport with either Na⁺, Li⁺, or H⁺, is a prototype of the Na⁺-coupled MFS transporters, but its sugar recognition mechanism has been a long-unsolved puzzle. Two high-resolution X-ray crystal structures of a Salmonella typhimurium MelB mutant with a bound ligand, either nitrophenyl-α-D-galactoside or dodecyl-β-D-melibioside, were refined to a resolution of 3.05 or 3.15 Å, respectively. In the substrate-binding site, the interaction of both galactosyl moieties on the two ligands with MelB_St are virturally same, so the sugar specificity determinant pocket can be recognized, and hence the molecu

SUBMITTER: Guan L 

PROVIDER: S-EPMC8329300 | biostudies-literature | 2021 Aug

REPOSITORIES: biostudies-literature