The crayfish plasma clotting protein: a vitellogenin-related protein responsible for clot formation in crustacean blood.
Coagulation in crayfish blood is based on the transglutaminase-mediated crosslinking of a specific plasma clotting protein. Here we report the cloning of the subunit of this clotting protein from a crayfish hepatopancreas cDNA library. The ORF encodes a protein of 1,721 amino acids, including a signal peptide of 15 amino acids. Sequence analysis reveals that the clotting protein is homologous to vitellogenins, which are proteins found in vitellogenic females of egg-laying animals. The clotting protein and vitellogenins are all lipoproteins and share a limited sequence similarity to certain other lipoproteins (e.g., mammalian apolipoprotein B and microsomal triglyceride transfer protein) and contain a stretch with similarity to the D domain of mammalian von Willebrand factor. The crayfish clotting protein is present in both sexes, unlike the female-specific vitellogenins. Electron microscopy was used to visualize individual clotting protein molecules and to study the transglutaminase-mediated clotting reaction. In the presence of an endogenous transglutaminase, the purified clotting protein molecules rapidly assemble into long, flexible chains that occasionally branch.
Department of Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Villavägen 6, S-752 36 Uppsala, Sweden.
M
M
Hall
R
R
Wang
R
R
van Antwerpen
L
L
Sottrup-Jensen
K
K
Söderhäll
D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001798:Blood Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D004064:Digestive System / Q000378:metabolism*; D005260:Female; D015723:Gene Library; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D008322:Mammals; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010058:Oviposition; D016133:Polymerase Chain Reaction; D021382:Protein Sorting Signals / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D011503:Transglutaminases / Q000378:metabolism; D014819:Vitellogenins / Q000737:chemistry / Q000235:genetics*; D014841:von Willebrand Factor / Q000737:chemistry / Q000235:genetics
D001798:Blood Proteins; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D008074:Lipoproteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D014819:Vitellogenins; C118118:plasma clotting protein, Pacifastacus leniusculus; D014841:von Willebrand Factor; D011503:Transglutaminases