2abh
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PHOSPHATE-BINDING PROTEIN (RE-REFINED)
OverviewOverview
Electrostatic 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.
About this StructureAbout this Structure
2ABH is a Single protein structure of sequence from Escherichia coli with PO4 as ligand. This structure superseeds the now removed PDB entry 1ABH. Full crystallographic information is available from OCA.
ReferenceReference
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
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