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.
Hall
M
M
Department of Comparative Physiology, Evolutionary Biology Centre, Uppsala University, Villavägen 6, S-752 36 Uppsala, Sweden.
Wang
R
R
van Antwerpen
R
R
Sottrup-Jensen
L
L
Söderhäll
K
K
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