The bacterial dicarboxylate transporter VcINDY uses a two-domain elevator-type mechanism

Mulligan, Christopher and Fenollar-Ferrer, Cristina and Fitzgerald, Gabriel A and Vergara-Jaque, Ariela and Kaufmann, Desirée and Li, Yan and Forrest, Lucy R and Mindell, Joseph A (2016) The bacterial dicarboxylate transporter VcINDY uses a two-domain elevator-type mechanism. Nature structural & molecular biology, 23 (3). pp. 256-263. ISSN 1545-9985. (doi:https://doi.org/10.1038/nsmb.3166) (Full text available)

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Abstract

Secondary transporters use alternating-access mechanisms to couple uphill substrate movement to downhill ion flux. Most known transporters use a 'rocking bundle' motion, wherein the protein moves around an immobile substrate-binding site. However, the glutamate-transporter homolog GltPh translocates its substrate-binding site vertically across the membrane, through an 'elevator' mechanism. Here, we used the 'repeat swap' approach to computationally predict the outward-facing state of the Na(+)/succinate transporter VcINDY, from Vibrio cholerae. Our model predicts a substantial elevator-like movement of VcINDY's substrate-binding site, with a vertical translation of ~15 Å and a rotation of ~43°. Our observation that multiple disulfide cross-links completely inhibit transport provides experimental confirmation of the model and demonstrates that such movement is essential. In contrast, cross-links across the VcINDY dimer interface preserve transport, thus revealing an absence of large-scale coupling between protomers.

Item Type: Article
Uncontrolled keywords: Computational biology and bioinformatics, Membrane proteins
Subjects: Q Science > QD Chemistry > QD431 Organic Chemistry- Biochemistry- Proteins, peptides, amino acids
Q Science > QP Physiology (Living systems) > QP517 Biochemistry
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Christopher Mulligan
Date Deposited: 10 May 2017 14:36 UTC
Last Modified: 27 Jun 2017 01:46 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/61674 (The current URI for this page, for reference purposes)
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