PROSITE documentation PDOC00186Albumin domain signature and profile
The following serum transport proteins are known to be evolutionary related [1,2,3]:
- Albumin (ALB), the main protein of plasma. It binds water, cations such as Ca++, Na+, K+, fatty acids, hormones, bilirubin and drugs. Its main function is the regulation of the colloidal osmotic pressure of blood.
- α-fetoprotein (AFP) (α-fetoglobulin). AFP is a fetal plasma protein which also binds various cations, fatty acids and bilirubin.
- Vitamin D-binding protein (VDB), also known as group-specific component or Gc-globulin. VDB binds to vitamin D and its metabolites as well as fatty acids.
- Afamin (or α-albumin), a protein whose biochemical role is not yet characterized.
Structurally, these proteins consist of two to seven homologous domains of about 190 amino acids. Each domain, consisting of 10 α-helices, is formed by two smaller subdomains and contains five or six internal disulfide bonds as shown in the following schematic representation [4].
+---+ +----+ +-----+
| | | | | |
xxCxxxxxxxxxxxxxxxxCCxxCxxxxCxxxxxCCxxxCxxxxxxxxxCxxxxxxxxxxxxxxCCxxxxCxxxx
| | | | | ***|********
+-----------------+ +------+ +---------------+
'C': conserved cysteine involved in a disulfide bond. '*': position of the pattern.
The signature pattern we derived is based on three conserved cysteines at the end of the domain. We built it in such a way that it can detect all 3 repeats in albumin and human afamin, the first two in AFP and the first one in VDB and rat afamin. We also developed a profile, which covers the entire albumin domain.
Last update:March 2009 / Text revised; profile added.
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PROSITE methods (with tools and information) covered by this documentation:
| 1 | Authors | Haefliger D.N. Moskaitis J.E. Schoenberg D.R. Wahli W. |
| Title | Amphibian albumins as members of the albumin, alpha-fetoprotein, vitamin D-binding protein multigene family. | |
| Source | J. Mol. Evol. 29:344-354(1989). | |
| PubMed ID | 2481749 |
| 2 | Authors | Schoentgen F. Metz-Boutigue M.-H. Jolles J. Constans J. Jolles P. |
| Title | Complete amino acid sequence of human vitamin D-binding protein (group-specific component): evidence of a three-fold internal homology as in serum albumin and alpha-fetoprotein. | |
| Source | Biochim. Biophys. Acta 871:189-198(1986). | |
| PubMed ID | 2423133 |
| 3 | Authors | Lichenstein H.S. Lyons D.E. Wurfel M.M. Johnson D.A. McGinley M.D. Leidli J.C. Trollinger D.B. Mayer J.P. Wright S.D. Zukowski M.M. |
| Title | Afamin is a new member of the albumin, alpha-fetoprotein, and vitamin D-binding protein gene family. | |
| Source | J. Biol. Chem. 269:18149-18154(1994). | |
| PubMed ID | 7517938 |
| 4 | Authors | He X.M. Carter D.C. |
| Title | Atomic structure and chemistry of human serum albumin. | |
| Source | Nature 358:209-215(1992). | |
| PubMed ID | 1630489 | |
| DOI | 10.1038/358209a0 |
| 5 | Authors | Verboven C. Rabijns A. De Maeyer M. Van Baelen H. Bouillon R. De Ranter C. |
| Title | A structural basis for the unique binding features of the human vitamin D-binding protein. | |
| Source | Nat. Struct. Biol. 9:131-136(2002). | |
| PubMed ID | 11799400 | |
| DOI | 10.1038/nsb754 |
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