Structural insights into sodium transport by the oxaloacetate decarboxylase sodium pump
- Tianjin Medical University, China
- Institute of Biophysics, Chinese Academy of Sciences, China
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, China
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 a subunit catalyzes carboxyl-transfer from oxaloacetate to biotin, the membrane integrated β subunit catalyzes the subsequent carboxyl-biotin decarboxylation and the coupled sodium transport, the γ subunit interacts with the a and β subunits and stabilizes the OAD complex. We present here structure of the Salmonella typhimurium OAD βγ sub-complex. The structure revealed that the β and γ subunits form a β3γ3 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 β subunit and the coupling between carboxyl-biotin decarboxylation and sodium transport by the OAD β subunit.
Data availability
The cryo-EM structure of the StOAD βγ sub-complex and related data have been deposited into the protein data bank (https://www.pdb.org) and the electron microscopy data bank (https://www.ebi.ac.uk/pdbe/emdb/), with the accession numbers 6IWW and EMD-9743, respectively. The crystal structure of the StOAD βγ sub-complex and the diffraction data have been deposited into the protein data bank with the accession number 6IVA. Source data for Figure 4c-d, Figure 4-figure supplement 1, Figure 5b-c, Figure 5-figure supplement 1, Figure 6a, Figure 6-figure supplement 1, and Figure 6-figure supplement 2a-b are provided.
Article and author information
Author details
Funding
National Natural Science Foundation of China (31870769)
- Song Xiang
National Natural Science Foundation of China (31570743)
- Song Xiang
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Xu et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structural insights into sodium transport by the oxaloacetate decarboxylase sodium pump
eLife 9:e53853.
https://doi.org/10.7554/eLife.53853
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