Identification of conformationally sensitive amino acids in the Na(+)/dicarboxylate symporter (SdcS).

ABSTRACT: The Na(+)/dicarboxylate symporter (SdcS) from Staphylococcus aureus is a homologue of the mammalian Na(+)/dicarboxylate cotransporters (NaDC1) from the solute carrier 13 (SLC13) family. This study examined succinate transport by SdcS heterologously expressed in Escherichia coli, using right-side-out (RSO) and inside-out (ISO) membrane vesicles. The K(m) values for succinate in RSO and ISO vesicles were similar, approximately 30 microM. The single cysteine of SdcS was replaced to produce the cysteine-less transporter, C457S, which demonstrated functional characteristics similar to those of the wild type. Single-cysteine mutants were made in SdcS-C457S at positions that are functionally important in mammalian NaDC1. Mutant N108C of SdcS was sensitive to chemical labeling by MTSET {[2-(trimet

SUBMITTER: Joshi AD 

PROVIDER: S-EPMC2666955 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature