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We are deeply saddened by the passing of Amos Bairoch (1957–2025), the creator of PROSITE. We wish to dedicate our latest paper, published shortly before his death, to him. He will always be a source of inspiration to us.
Our deepest condolences go out to his family and friends, and to all those who had the privilege of working with him. Rest in peace, Amos. Your work will live on long after you are gone.
Amos Bairoch

PROSITE documentation PDOC00186
Albumin domain signature and profile


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PURL: https://purl.expasy.org/prosite/documentation/PDOC00186

Description

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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Technical section

PROSITE methods (with tools and information) covered by this documentation:

ALBUMIN_2, PS51438; Albumin domain profile  (MATRIX)

ALBUMIN_1, PS00212; Albumin domain signature  (PATTERN)


References

1AuthorsHaefliger D.N. Moskaitis J.E. Schoenberg D.R. Wahli W.
TitleAmphibian albumins as members of the albumin, alpha-fetoprotein, vitamin D-binding protein multigene family.
SourceJ. Mol. Evol. 29:344-354(1989).
PubMed ID2481749

2AuthorsSchoentgen F. Metz-Boutigue M.-H. Jolles J. Constans J. Jolles P.
TitleComplete 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.
SourceBiochim. Biophys. Acta 871:189-198(1986).
PubMed ID2423133

3AuthorsLichenstein 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.
TitleAfamin is a new member of the albumin, alpha-fetoprotein, and vitamin D-binding protein gene family.
SourceJ. Biol. Chem. 269:18149-18154(1994).
PubMed ID7517938

4AuthorsHe X.M. Carter D.C.
TitleAtomic structure and chemistry of human serum albumin.
SourceNature 358:209-215(1992).
PubMed ID1630489
DOI10.1038/358209a0

5AuthorsVerboven C. Rabijns A. De Maeyer M. Van Baelen H. Bouillon R. De Ranter C.
TitleA structural basis for the unique binding features of the human vitamin D-binding protein.
SourceNat. Struct. Biol. 9:131-136(2002).
PubMed ID11799400
DOI10.1038/nsb754



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