1aoc
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JAPANESE HORSESHOE CRAB COAGULOGEN
OverviewOverview
The clotting cascade system of the horseshoe crab (Limulus) is involved in, both haemostasis and host defence. The cascade results in the conversion, of coagulogen, a soluble protein, into an insoluble coagulin gel. The, clotting enzyme excises the fragment peptide C from coagulogen, giving, rise to aggregation of the monomers. The crystal structure of coagulogen, reveals an elongated molecule that embraces the helical peptide C, fragment. Cleavage and removal of the peptide C would expose an extended, hydrophobic cove, which could interact with the hydrophobic edge of a, second molecule, leading to a polymeric fibre. The C-terminal half of the, coagulogen molecule exhibits a striking topological similarity to the, neurotrophin nerve growth factor (NGF), providing the first evidence for a, neurotrophin fold in invertebrates. Similarities between coagulogen and, Spatzle, the Drosophila ligand of the receptor Toll, suggest that the, neurotrophin fold might be considered more ancient and widespread than, previously realized.
About this StructureAbout this Structure
1AOC is a Single protein structure of sequence from Tachypleus tridentatus with SO4 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a coagulogen, the clotting protein from horseshoe crab: a structural homologue of nerve growth factor., Bergner A, Oganessyan V, Muta T, Iwanaga S, Typke D, Huber R, Bode W, EMBO J. 1996 Dec 16;15(24):6789-97. PMID:9003754
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