Structural comparison of cupredoxin domains: Domain recycling to construct proteins with novel functions

• Published in: Protein science 1997-04, Vol.6 (4), p.761-770
• Main Authors: Murphy, MICHAEL E. P., Lindley, Peter F., Adman, Elinor T.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Azurin - analogs & derivatives; Azurin - chemistry; Azurin - classification; Bacterial Proteins - chemistry; Bacterial Proteins - classification; Binding Sites; Conserved Sequence; cupredoxin; domain phylogeny; Humans; Molecular Sequence Data; Phylogeny; Plant Proteins - chemistry; Plant Proteins - classification; Protein Conformation; Recombinant Proteins - chemistry; Sequence Homology, Amino Acid; structural comparison
• ISSN: 0961-8368; 1469-896X
• DOI: 10.1002/pro.5560060402

The three‐dimensional structures of the copper‐containing enzymes ascorbate oxidase, ceruloplasmin, and nitrite reductase, comprised of multiple domains with a cupredoxin fold, are consistent with having evolved from a common ancestor. The presence or absence of copper sites has complicated ascertaining the structural and evolutionary relationship among these and related proteins. Simultaneous structural superposition of the enzyme domains and their known cupredoxin relatives shows clearly that there are at least six cupredoxin classes, and that the evolution of the conserved core of these domains is independent of the presence or absence of copper sites. Relationships among the variable loops in these structures show that the two‐domain ancestor of the blue oxidases contained a trinuclear‐copper interface but could not have functioned in a monomeric state. Comparison of the sequence of the copper‐containing, iron‐regulating protein. Ferrous transport (Fet3) from yeast to the structurally defined core and loop residues of the cupredoxins suggests specific residues that could be involved in the ferroxidase activity of Fet3.