Desolvation of the substrate binding protein TauA dictates ligand specificity for the alkanesulfonate ABC importer TauABC
File(s)
Published version
Author(s)
Qu, F
ElOmari, K
Wagner, A
De Simone, A
Beis, Konstantinos
Type
Journal Article
Abstract
Under limiting sulfur availability, bacteria can assimilate sulfur from alkanesulfonates. Bacteria utilize ATP-binding cassette (ABC) transporters to internalise them for further processing to release sulfur. In gram-negative bacteria the TauABC and SsuABC ensure internalization, although, these two systems have common substrates, the former has been characterised as a taurine specific system. TauA and SsuA are substrate binding proteins (SBPs) that bind and bring the alkanesulfonates to the ABC importer for transport. Here, we have determined the crystal structure of TauA and have characterised its thermodynamic binding parameters by isothermal titration calorimetry in complex with taurine and different alkanesulfonates. Our structures revealed that the coordination of the alkanesulfonates is conserved, with the exception of Asp205 that is absent in SsuA, but the thermodynamic parameters revealed a very high enthalpic penalty cost for binding of the other alkanesulfonates relative to taurine. Our molecular dynamic simulations indicated that the different levels of hydration of the binding site contributed to the selectivity for taurine over the other alkanesulfonates. Such selectivity mechanism is very likely to be employed by other SBPs of ABC transporters.
Date Issued
2019-12-10
Date Acceptance
2019-11-22
Citation
Biochemical Journal, 2019, 476 (23), pp.3649-3660
ISSN
0264-6021
Publisher
Portland Press
Start Page
3649
End Page
3660
Journal / Book Title
Biochemical Journal
Volume
476
Issue
23
Copyright Statement
© 2019 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY)
Sponsor
Medical Research Council (MRC)
Identifier
https://portlandpress.com/biochemj/article/doi/10.1042/BCJ20190779/221299/Desolvation-of-the-substrate-binding-protein-TauA
Grant Number
MR/N020103/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
ESCHERICHIA-COLI
MODEL
TAURINE
RECOGNITION
HYDRATION
WATER
ABC transport proteins
crystallography
molecular dynamics
thermodynamics
03 Chemical Sciences
06 Biological Sciences
11 Medical and Health Sciences
Biochemistry & Molecular Biology
Publication Status
Published
Date Publish Online
2019-12-10