2abh
PHOSPHATE-BINDING PROTEIN (RE-REFINED)PHOSPHATE-BINDING PROTEIN (RE-REFINED)
Structural highlights
Function[PSTS_ECOLI] Part of the ABC transporter complex PstSACB involved in phosphate import. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedElectrostatic interactions are among the key forces determining the structure and function of proteins. These are exemplified in the liganded form of the receptor, a phosphate binding protein from Escherichia coli. The phosphate, completely dehydrated and buried in the receptor, is bound by 12 hydrogen bonds as well as a salt link with Arg 135. We have modulated the ionic attraction while preserving the hydrogen bonds by mutating Asp 137, also salt linked to Arg 135, to Asn, Gly or Thr. High-resolution crystallographic analysis revealed that Gly and Thr (but not Asn) mutant proteins have incorporated a more electronegative Cl- in place of the Asp carboxylate. That no dramatic effect on phosphate affinity was produced by these ionic perturbations indicates a major role for hydrogen bonds and other local dipoles in the binding and charge stabilization of ionic ligands. Modulation of a salt link does not affect binding of phosphate to its specific active transport receptor.,Yao N, Ledvina PS, Choudhary A, Quiocho FA Biochemistry. 1996 Feb 20;35(7):2079-85. PMID:8652549[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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