PROSITE documentation PDOC00906
Anaphylatoxin domain signature and profile


Anaphylatoxins [1] are mediators of local inflammatory process that act by inducing smooth muscle contraction. There are three different anaphylatoxins: C3a, C4a and C5a. They are peptides of about 75 amino-acid residues that are derived from the proteolytic degradation of complement C3, C4 and C5 and which contains six disulfide-bonded cysteines [2] (see the schematic representation below).

            +-------------|------------+       |
            |             |            |       |
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'C': conserved cysteine involved in a disulfide bond.

This cysteine-rich region shares similarity with a three times repeated domain found in the mammalian extracellular matrix proteins fibulins 1 and 2 [3,4]. The three disulfide bonds are conserved in the first and last repeats, but the first disulfide bond is missing in the second repeat.

Our consensus pattern spans the entire cysteine-rich domain.

Last update:

May 2004 / Text revised.


Technical section

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

ANAPHYLATOXIN_2, PS01178; Anaphylatoxin domain profile  (MATRIX)

ANAPHYLATOXIN_1, PS01177; Anaphylatoxin domain signature  (PATTERN)


1AuthorsHugli T.E.
TitleBiochemistry and biology of anaphylatoxins.
SourceComplement 3:111-127(1986).
PubMed ID3542363

2AuthorsHuber R. Scholze H. Paques E.P. Deisenhofer J.
TitleCrystal structure analysis and molecular model of human C3a anaphylatoxin.
SourceHoppe-Seyler's Z. Physiol. Chem. 361:1389-1399(1980).
PubMed ID7439885

3AuthorsArgraves W.S. Tran H. Burgess W.H. Dickerson K.
TitleFibulin is an extracellular matrix and plasma glycoprotein with repeated domain structure.
SourceJ. Cell Biol. 111:3155-3164(1990).
PubMed ID2269669

4AuthorsPan T.-C. Sasaki T. Zhang R.-Z. Faessler R. Timpl R. Chu M.L.
TitleStructure and expression of fibulin-2, a novel extracellular matrix protein with multiple EGF-like repeats and consensus motifs for calcium binding.
SourceJ. Cell Biol. 123:1269-1277(1993).
PubMed ID8245130

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