1QUK

PHOSPHATE-BINDING PROTEIN MUTANT WITH ASP 137 REPLACED BY ASN COMPLEX WITH PHOSPHATE

Summary for 1QUK

• Entry DOI: 10.2210/pdb1quk/pdb
• Descriptor: PHOSPHATE-BINDING PROTEIN, PHOSPHATE ION (3 entities in total)
• Functional Keywords: binding protein, phosphate transport
• Biological source: Escherichia coli
• Cellular location: Periplasm: P06128
• Total number of polymer chains: 1
• Total formula weight: 34551.58

Authors

Yao, N.,Choudhary, A.,Ledvina, P.S.,Quiocho, F.A. (deposition date: 1995-11-11, release date: 1996-07-11, Last modification date: 2024-02-14)

Primary citation

Yao, N.,Ledvina, P.S.,Choudhary, A.,Quiocho, F.A.
Modulation of a salt link does not affect binding of phosphate to its specific active transport receptor.
Biochemistry, 35:2079-2085, 1996

PubMed Abstract: 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.

PubMed: 8652549
DOI: 10.1021/bi952686r

Experimental method

X-RAY DIFFRACTION (1.7 Å)