Crystal structure of Pseudomonas aeruginosa apo‐azurin at 1.85 Å resolution

FEBS Letters

van de Kamp, Mart¹  Huber, Robert¹  Nar, Herbert¹  Messerschmidt, Albrecht¹  Canters, Gerard W.² 

[1] Max Planck Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz, 8033 Martinsried bei München, Germany;Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands

关键词: Azurin;    Apo-protein;    Copper;    Metal incorporation;    Conformational change;   

DOI  :  10.1016/0014-5793(92)80981-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The 3D structure of apo-azurin from Pseudomonas aeruginosa has been determined at 1.85 Å 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 Å and 1.6 Å. 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 or apo-azurin recorded as a function or 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.

【 授权许可】

Unknown