Azurin
Azurin is a small, periplasmic, bacterial blue copper protein found in Pseudomonas, Bordetella, or Alcaligenes bacteria. Azurin moderates single-electron transfer between enzymes associated with the cytochrome chain by undergoing oxidation-reduction between Cu(I) and Cu(II). Each monomer of an azurin tetramer has a molecular weight of approximately 14kDa, contains a single copper atom, is intensively blue, and has a fluorescence emission band centered at 308 nm.
| Azurin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Azurin tetramer, Pseudomonas aeruginosa | |||||||||
| Identifiers | |||||||||
| Symbol | Copper-bind | ||||||||
| Pfam | PF00127 | ||||||||
| SCOP2 | 5azu / SCOPe / SUPFAM | ||||||||
| CDD | cd13922 | ||||||||
| |||||||||
Azurins and pseudoazurins participate in the denitrification processes in bacteria., including the gram-negative bacteria Pseudomonas aeruginosa, by interacting with cytochrome c551. Azurin from P aeruginosa is a type I blue copper protein (cupredoxin), while cytochrome c551 (9 kDa) is a haem-containing cytochrome. Azurin possesses a relatively large hydrophobic patch close to the active site, and two residues in this hydrophobic patch, Met-44 and Met-64, are believed to be involved in its interaction with the redox partners cytochrome c551 and nitrite reductase.
Although unrelated to its electron-transfer property, azurin has been found to have anticancer properties through its interaction with tumor-suppressor protein p53.