{PDOC00186}
{PS00212; ALBUMIN_1}
{PS51438; ALBUMIN_2}
{BEGIN}
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* Albumin domain signature and profile *
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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.
 - Alpha-fetoprotein (AFP) (alpha-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 alpha-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 alpha-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.

-Consensus pattern: [FY]-x(6)-C-C-x(2)-{C}-x(4)-C-[LFY]-x(6)-[LIVMFYW]
                    [The 3 C's are involved in disulfide bonds]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: mammalian CD63 antigen.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: March 2009 / Text revised; profile added.

[ 1] Haefliger D.N., Moskaitis J.E., Schoenberg D.R., Wahli W.
     "Amphibian albumins as members of the albumin, alpha-fetoprotein,
     vitamin D-binding protein multigene family."
     J. Mol. Evol. 29:344-354(1989).
     PubMed=2481749
[ 2] Schoentgen F., Metz-Boutigue M.-H., Jolles J., Constans J., Jolles P.
     "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."
     Biochim. Biophys. Acta 871:189-198(1986).
     PubMed=2423133
[ 3] 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.
     "Afamin is a new member of the albumin, alpha-fetoprotein, and vitamin
     D-binding protein gene family."
     J. Biol. Chem. 269:18149-18154(1994).
     PubMed=7517938
[ 4] He X.M., Carter D.C.
     "Atomic structure and chemistry of human serum albumin."
     Nature 358:209-215(1992).
     PubMed=1630489; DOI=10.1038/358209a0
[ 5] Verboven C., Rabijns A., De Maeyer M., Van Baelen H., Bouillon R.,
     De Ranter C.
     "A structural basis for the unique binding features of the human
     vitamin D-binding protein."
     Nat. Struct. Biol. 9:131-136(2002).
     PubMed=11799400; DOI=10.1038/nsb754

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