Molecular mechanism underlying transport and allosteric inhibition of bicarbonate transporter SbtA.

ABSTRACT: SbtA is a high-affinity, sodium-dependent bicarbonate transporter found in the cyanobacterial CO₂-concentrating mechanism (CCM). SbtA forms a complex with SbtB, while SbtB allosterically regulates the transport activity of SbtA by binding with adenyl nucleotides. The underlying mechanism of transport and regulation of SbtA is largely unknown. In this study, we report the three-dimensional structures of the cyanobacterial Synechocystis sp. PCC 6803 SbtA-SbtB complex in both the presence and absence of HCO₃^- and/or AMP at 2.7 Å and 3.2 Å resolution. An analysis of the inward-facing state of the SbtA structure reveals the HCO₃^-/Na⁺ binding site, providing evidence for the functional unit as a trimer. A structural compari

SUBMITTER: Fang S 

PROVIDER: S-EPMC8179158 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature