Download MendeleyCrystal Structure of Pseudomonas Aeruginosa Apo-Azurin at 1.85 A Resolution.
Nar, H., Messerschmidt, A., Huber, R., Van De Kamp, M., Canters, G.W.(1992) FEBS Lett 306: 119
- PubMed: 1633865
- DOI: https://doi.org/10.1016/0014-5793(92)80981-l
- Primary Citation of Related Structures:
1E65 - PubMed Abstract:
The 3D structure of apo-azurin from Pseudomonas aeruginosa has been determined at 1.85 A resolution. The crystal structure is composed of two different molecular forms of apo-azurin arranged as hetero-dimers in the tetramer of the asymmetric unit. Form 1 closely resembles the holo-protein lacking copper. Form 2 shows differences in the metal binding site region induced by the incorporation of a solvent molecule into this site. The positions of the copper ligands His46 and His117 are shifted by 0.6 A and 1.6 A. The His117 side chain adopts a position at the surface of the protein, thereby facilitating access to the copper site. The presence of two different molecular forms of apo-azurin in the crystal lattice may reflect an equilibrium between the two forms in solution. 1H-NMR spectra of apo-azurin recorded as a function of pH show that at high pH the line broadening of His35, His46 and His117 resonances is consistent with an interconversion between forms 1 and 2. At low pH, no broadening is observed. This may indicate that here the interconversion is fast on the NMR timescale.
Organizational Affiliation:
Max Planck Institut für Biochemie, Abteilung Strukturforschung, Martinsried bei München, Germany.
