Primary structure characterization of a Rhodocyclus tenuis diheme cytochrome c reveals the existence of two different classes of low-potential diheme cytochromes c in purple phototropic bacteria
| Autor: | Gonzalez Van Driessche, K. Backers, Bart Devreese, Ann Brigé, Terrance E. Meyer, Jozef Van Beeumen, Michael A. Cusanovich |
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| Rok vydání: | 2000 |
| Předmět: |
Cytochrome
Heme binding Rhodocyclus tenuis Stereochemistry Molecular Sequence Data Biophysics Cytochrome c Group Heme medicine.disease_cause Ligands Biochemistry Mass Spectrometry chemistry.chemical_compound Rhodobacter sphaeroides Bacterial Proteins Drug Stability Species Specificity Pseudomonas medicine Amino Acid Sequence Molecular Biology Peptide sequence Conserved Sequence Binding Sites biology Edman degradation Sequence Homology Amino Acid Betaproteobacteria biology.organism_classification Pseudomonas stutzeri chemistry Genes Bacterial biology.protein |
| Zdroj: | Archives of biochemistry and biophysics. 381(1) |
| ISSN: | 0003-9861 |
| Popis: | The complete amino acid sequence of a 26-kDa low redox potential cytochrome c-551 from Rhodocyclus tenuis was determined by a combination of Edman degradation and mass spectrometry. There are 240 residues including two heme binding sites at positions 41, 44, 128, and 132. There is no evidence for gene doubling. The only known homolog of Rc. tenuis cytochrome c-551 is the diheme cytochrome c-552 from Pseudomonas stutzeri which contains 268 residues and heme binding sites at nearly identical positions. There is 44% overall identity between the Rc. tenuis and Ps. stutzeri cytochromes with 10 internal insertions and deletions. The Ps. stutzeri cytochrome is part of a denitrification gene cluster, whereas Rc. tenuis is incapable of denitrification, suggesting different functional roles for the cytochromes. Histidines at positions 45 and 133 are the fifth heme ligands and conserved histidines at positions 29, 209, and 218 and conserved methionines at positions 114 and 139 are potential sixth heme ligands. There is no obvious homology to the low-potential diheme cytochromes characterized from other purple bacterial species such as Rhodobacter sphaeroides. There are therefore at least two classes of low-potential diheme cytochromes c found in phototrophic bacteria. There is no more than 11% helical secondary structure in Rc. tenuis cytochrome c-551 suggesting that there is no relationship to class I or class II c-type cytochromes. |
| Databáze: | OpenAIRE |
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