Structure of metal site in azurin, met 121 mutants of azurin, and stellacyanin investigated by 111m Cd Perturbed Angular Correlation (PAC)
| Autor: | Morten J. Bjerrum, Tilman Butz, Lars Hemmingsen, Marie-Louise Andersen, Gerard W. Canters, Örjan Hansson, Carla W. G. Hoitink, W. Tröger, Eva Danielsen, Rogert Bauer, Göran Karlsson, Albrecht Messerschmidt |
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| Jazyk: | angličtina |
| Rok vydání: | 1995 |
| Předmět: |
Stereochemistry
Mutant Alcaligenes denitrificans Biochemistry Metal chemistry.chemical_compound Methionine Azurin Metalloproteins Molecular Biology Plant Proteins chemistry.chemical_classification Stellacyanin Fourier Analysis biology Chemistry Spectrum Analysis Indium Radioisotopes Wild type Cell Biology biology.organism_classification Amino acid Crystallography visual_art Mutation visual_art.visual_art_medium biology.protein Cadmium |
| Popis: | The geometries of the metal sites in cadmium-substituted azurins have been investigated by 111m Cd perturbed angular correlation (PAC). The study includes wild type azurin as well as Met 121 mutants of azurin, where methionine has been substituted by Ala, Asn, Asp, Gln, Glu, and Leu. The nuclear quadrupole interaction of wild type azurin analyzed in the angular overlap model is well described as coordination of His 46 , His 117 , and Cys 112 and cannot be described by coordination of Met 121 and/or Gly 45 . For most of the mutants, there exist two coordination geometries of the cadmium ion. With the exception of the Glu and Asp mutants, one of the conformations is similar to the wild type conformation. The other coordination geometries are either best described by a coordinating water molecule close to the original methionine position or by coordination by the substituting amino acid. These experiments show that even though the methionine does not coordinate it plays an important role for the geometry of the metal site. The nuclear quadrupole interaction of stellacyanin was also measured. The value resembles the most prominent nuclear quadrupole interaction of the Met 121121 → Gln mutant of Alcaligenes denitrificans azurin, indicating that the structures of the two metal sites are similar. |
| Databáze: | OpenAIRE |
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