Structural insights into sodium transport by the oxaloacetate decarboxylase sodium pump.

ABSTRACT: The oxaloacetate decarboxylase sodium pump (OAD) is a unique primary-active transporter that utilizes the free energy derived from oxaloacetate decarboxylation for sodium transport across the cell membrane. It is composed of 3 subunits: the ? subunit catalyzes carboxyl-transfer from oxaloacetate to biotin, the membrane integrated ? subunit catalyzes the subsequent carboxyl-biotin decarboxylation and the coupled sodium transport, the ? subunit interacts with the ? and ? subunits and stabilizes the OAD complex. We present here structure of the Salmonella typhimurium OAD ?? sub-complex. The structure revealed that the ? and ? subunits form a ?3?3 hetero-hexamer with extensive interactions between the subunits and shed light on the OAD holo-enzyme assembly. Structure-guided functional studies provided insights into the sodium binding sites in the ? subunit and the coupling between carboxyl-biotin decarboxylation and sodium transport by the OAD ? subunit.

SUBMITTER: Xu X 

PROVIDER: S-EPMC7274780 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature