{PDOC00758}
{PS00985; SPERMADHESIN_1}
{PS00986; SPERMADHESIN_2}
{BEGIN}
***********************************
* Spermadhesins family signatures *
***********************************

A family of mammalian sperm  proteins  has been  recently characterized [1,2].
The proteins that are currently known to belong to this family are:

 - Pig spermadhesins AQN-1, AQN-3 and AWN-1. These proteins are synthesized by
   the sexual  accessory  glands  and becomes attached to the sperm surface at
   the time  of  ejaculation. They bind to the ZP-glycoproteins and to heparin
   and seems to inhibit serine protease inhibitors.
 - Bovine acidic seminal fluid protein (ASFP), which seems to be growth factor
   with effects on ovarian granulosa cells.
 - Pig major seminal plasma glycoproteins PSP-I and PSP-II.
 - Bovine seminal plasma protein Z13.

As shown in the following schematic representation these proteins,  which have
from 110 to 130 amino acid residues, contain four conserved cysteines involved
in two disulfide bonds.

                +---------+           +---------+
                |         |           |         |
            xxxxCxxxxxxxxxCxxxxxxxxxxxCxxxxxxxxxCxxxxxxxxxxxxxxxxxx
                ************          ***********

'C': conserved cysteine involved in a disulfide bond.
'*': position of the patterns.

Structurally, the spermadhesins consist of a CUB domain [3] (see <PDOC00908>).

-Consensus pattern: C-G-x(2)-[LIY]-x(4)-G-x-I-x(9)-C-x-W-T
                    [The 2 C's are involved in a disulfide bond]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: C-x-K-E-x-[LIVM]-E-[LIVM]-x-[DE]-x(3)-[GSE]-x(5)-K-x-C
                    [The 2 C's are involved in a disulfide bond]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: May 2004 / Text revised.

[ 1] Calvete J.J., Solis D., Sanz L., Diaz-Maurino T., Schafer W., Mann K.,
     Topfer-Petersen E.
     "Characterization of two glycosylated boar spermadhesins."
     Eur. J. Biochem. 218:719-725(1993).
     PubMed=8269963
[ 2] Kwok S.C.M., Yang D., Dai G., Soares M.J., Chen S., McMurtry J.P.
     "Molecular cloning and sequence analysis of two porcine seminal
     proteins, PSP-I and PSP-II: new members of the spermadhesin family."
     DNA Cell Biol. 12:605-610(1993).
     PubMed=8397818
[ 3] Bork P., Beckmann G.
     "The CUB domain. A widespread module in developmentally regulated
     proteins."
     J. Mol. Biol. 231:539-545(1993).
     PubMed=8510165

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