Search

Research has been conducted on HI0719 protein from Haemophilus influenzae with no definitive molecular function. The description three-dimensional structure in solution of HI0719 and the evaluation of its biochemical functions are described.

The crystal structure of the Met121Glu azurin mutant of Pseudomonas aeruginosa has been determined at 2.3 angstroms. Azurin is a small blue copper protein, with a molecular mass between nine and 18 kDa, found in the electron-transfer chains of plants and bacteria. Results indicate that the glutamic acid residue coordinates the copper ion at a distance of 2.2 angstroms. The blue shift at 614 and 460 nm is due to the introduction of a negative charge very close to the copper ion coupled by the movement of the copper atom out of the major ligand plane.

Electron and optical paramagnetic resonance spectroscopic analyses of the binding of exogenous ligands to the Met121X mutant of Pseudomonas aeruginosa azurin indicate that small molecules bind to copper through the cavity formed by the side chain of Met121. The strong absorption bands of azurin develop due to S-to-Cu charge transfer transitions. Small carboxylic acids react strongly with metal ions and copper attains a type 1.5 character. The EPR spectra of azurin are discussed.