6st1

Taurine ABC transporter substrate binding protein TauA from E. coli in complex with 2-(N-Morpholino)ethanesulfonic acid (MES)

spinqualitylabelsall models 6st1, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6st1 is a 2 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: GOL, IOD, MES Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TAUA_ECOLI Part of a binding-protein-dependent transport system for taurine. Publication Abstract from PubMed 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 characterized 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 characterized 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 from 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. Desolvation of the substrate-binding protein TauA dictates ligand specificity for the alkanesulfonate ABC importer TauABC.,Qu F, ElOmari K, Wagner A, De Simone A, Beis K Biochem J. 2019 Dec 12;476(23):3649-3660. doi: 10.1042/BCJ20190779. PMID:31802112 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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