Proteolytic digestion of non-collagenous basement membrane proteins by the hemorrhagic metalloproteinase Ht-e from Crotalus atrox venom.
Hemorrhagic toxin e (Ht-e), a metalloproteinase isolated from the venom of the Western Diamondback rattlesnake Crotalus atrox, digests laminin and nidogen, both in their isolated forms and when present in a purified soluble complex. The only common site of cleavage by Ht-e of isolated nidogen and nidogen when complexed with laminin is at amino acid residue 336 in the amino terminal domain. Additionally, nidogen in complex with laminin is also cleaved at sites 322, 351 and 840 as determined by sequence analysis and site 953 as proposed from the molecular mass of a digestion product. Isolated nidogen, on the other hand, was cleaved at amino acid residues 75, 336, 402, and 920, as determined by sequence determinations and approximately at residues 296, 478, 625 and 702 as proposed from the molecular mass values of the generated polypeptide chains. Products from the proteolytic cleavage of the A and B2 chains of laminin were observed with the sites of cleavage determined to be at position 2666 in the laminin A chain and position 1238 in the laminin B2 chain. The laminin digestion products were identical regardless of whether nidogen was present in a complex with the laminin chains.
Baramova
E N
EN
Department of Microbiology, University of Virginia Medical School, Charlottesville 22908.
Shannon
J D
JD
Fox
J W
JW
Bjarnason
J B
JB
D000595:Amino Acid Sequence; D000818:Animals; D001485:Basement Membrane / Q000378:metabolism*; D001665:Binding Sites; D003435:Crotalid Venoms / Q000378:metabolism*; D066298:In Vitro Techniques; D007797:Laminin / Q000737:chemistry / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism; D008666:Metalloendopeptidases / Q000378:metabolism*; D008969:Molecular Sequence Data
D003435:Crotalid Venoms; D007797:Laminin; D008562:Membrane Glycoproteins; C032814:hemorrhagin components (Crotalid); C029967:nidogen; D008666:Metalloendopeptidases