Structure of Pseudomonas aeruginosai zinc azurin mutant Asn47Asp at 2.4 A resolution.Sjolin, L., Tsai, L.C., Langer, V., Pascher, T., Karlsson, G., Nordling, M., Nar, H.
(1993) Acta Crystallogr.,Sect.D 49: 449-457
- PubMed: 15299504
- DOI: 10.1107/S0907444993005207
- PubMed Abstract:
The Pseudomonas aeruginosa azurin mutant Asn47Asp has been isolated, its spectroscopic and kinetic properties characterized, and the X-ray crystal structure of its zinc derivative determined. While the optical and electron paramagnetic resonance spec ...
The Pseudomonas aeruginosa azurin mutant Asn47Asp has been isolated, its spectroscopic and kinetic properties characterized, and the X-ray crystal structure of its zinc derivative determined. While the optical and electron paramagnetic resonance spectra as well as the electron-transfer activity of the mutant are very similar to the wild-type values, the Asn47Asp reduction potential is slightly increased by 20 mV. The mutant crystallized in the orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 57.8, b = 81.5 and c = 112.6 A. There are four molecules in the asymmetric unit, packed as a tetramer which consists of two independent dimers. The zinc site of this mutant structure is similar to the wild-type zinc azurin and, in particular, the metal-binding site is almost identical to the site found in the wild-type zinc-azurin structure [Nar, Huber, Messerschmidt, Filippou, Barth, Jaquinod, Kamp & Canters (1992). Eur. J. Biochem. 205, 1123-1129]. The Asp47 side chain at that mutation site takes on a very similar orientation to Asn47 in the wild-type structure preserving the two hydrogen bonds with the neighbouring Thr113 NH and O(gamma)H. Therefore, the increased reduction potential of the mutant is probably a result of an altered charge distribution close to the metal site.
Department of Inorganic Chemistry, Chalmers University of Technology and the University of Göteborg, Sweden.