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* Pentaxin family signature *
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Pentaxins (or pentraxins) [1]  are  a  family  of  proteins  which show, under
electron  microscopy,  a  discoid  arrangement  of  five  noncovalently  bound
subunits. Proteins known to belong to this family are:

 - C-reactive protein (CRP), a protein which, in  mammals, is expressed during
   acute phase response to tissue injury or inflammation. CRP displays several
   functions  associated  with   host  defense:  it  promotes   agglutination,
   bacterial capsular swelling, phagocytosis  and complement  fixation through
   its calcium-dependent binding  to phosphorylcholine.   CRPs  have also been
   sequenced [2] in an invertebrate, the  Atlantic horseshoe  crab, where they
   are a normal constituent of the hemolymph.
 - Serum Amyloid P-component (SAP), a precursor of amyloid  component P  which
   is found in basement membrane and is associated with amyloid deposits.
 - Hamster female protein (FP) [3], a  plasma  protein  whose concentration is
   altered by sex steroids and stimuli that elicit an acute phase response.
 - Human PTX3 [4]. PTX3 is a  cytokine-induced protein  whose  function is not
   yet known and which contains a pentaxin domain in its C-terminal half.

The sequences of the different members of this family are quite conserved.  As
a signature,  we  selected  a six residue pattern  which  includes a  cysteine
known to be involved in a disulfide bridge in CRPs and SAP.

-Consensus pattern: H-x-C-x-[ST]-W-x-S
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: October 1993 / Text revised.

[ 1] Pepys M.B., Baltz M.L.
     Adv. Immunol. 34:141-212(1983).
[ 2] Nguyen N.Y., Suzuki A., Boykins R.A., Liu T.-Y.
     J. Biol. Chem. 261:10456-10465(1986).
[ 3] Dowton S.B., Woods D.E., Mantzouranis E.C., Colten H.R.
     Science 228:1206-1208(1985).
[ 4] Breviario F., d'Aniello E.M., Golay J., Peri G., Bottazi B., Bairoch A.,
     Saccone S., Marzella R., Predazzi V., Rocchi M., Della Valle G.,
     Dejana E., Mantovani A., Introna M.
     J. Biol. Chem. 267:22190-22197(1992).