1etj | pdb_00001etj
AZURIN MUTANT WITH MET 121 REPLACED BY GLU
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Overview
The Met121Glu azurin mutant has been crystallized and the structure, determined at a resolution of 2.3 A. In the crystal structure a carboxyl, oxygen of Met121Glu is coordinated to the metal at a distance of 2.2 A., Single-crystal resonance Raman spectroscopy was used to show that the, glutamic acid residue in the copper site was in the protonated state., Titration of this residue gives rise to a number of unusual, pH-dependent, properties: as the pH is increased from 4 to 8, the S(Cys)-Cu, ligand-to-metal charge transfer bands are blue shifted and their intensity, ratio is reversed, the EPR signal changes from type 1 copper to a new form, of protein-bound copper, and the redox potential changes from 370 to 180, mV. The spectroscopic changes in this pH interval are consistent with a, two-state model. From the pH dependence of the optical and EPR spectra, pKa = 5.0 for the glutamic acid in the oxidized protein was determined.
About this Structure
1ETJ is a Single protein structure of sequence from Pseudomonas aeruginosa with CU as ligand. Full crystallographic information is available from OCA.
Reference
X-ray structure determination and characterization of the Pseudomonas aeruginosa azurin mutant Met121Glu., Karlsson BG, Tsai LC, Nar H, Sanders-Loehr J, Bonander N, Langer V, Sjolin L, Biochemistry. 1997 Apr 8;36(14):4089-95. PMID:9100002
Page seeded by OCA on Tue Nov 20 14:18:04 2007
