Structural and functional analyses of DM43, a snake venom metalloproteinase inhibitor from Didelphis marsupialis serum.
DM43, an opossum serum protein inhibitor of snake venom metalloproteinases, has been completely sequenced, and its disulfide bond pattern has been experimentally determined. It shows homology to human alpha(1)B-glycoprotein, a plasma protein of unknown function and a member of the immunoglobulin supergene family. Size exclusion and dynamic laser light scattering data indicated that two monomers of DM43, each composed of three immunoglobulin-like domains, associated to form a homodimer in solution. Analysis of its glycan moiety showed the presence of N-acetylglucosamine, mannose, galactose, and sialic acid, most probably forming four biantennary N-linked chains. DM43 inhibited the fibrinogenolytic activities of bothrolysin and jararhagin and formed 1:1 stoichiometric stable complexes with both metalloproteinases. DM43 was ineffective against atrolysin C or A. No complex formation was detected between DM43 and jararhagin C, indicating the essential role of the metalloproteinase domain for interaction. Homology modeling based on the crystal structure of a killer cell inhibitory receptor suggested the existence of an I-type Ig fold, a hydrophobic dimerization surface and six surface loops potentially forming the metalloproteinase-binding surface on DM43.
Neves-Ferreira
Ana G C
AG
Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fiocruz, 21045-900 Rio de Janeiro, Brazil.
Perales
Jonas
J
Fox
Jay W
JW
Shannon
John D
JD
Makino
Débora L
DL
Garratt
Richard C
RC
Domont
Gilberto B
GB
D000595:Amino Acid Sequence; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D017837:Bothrops; D003435:Crotalid Venoms / Q000201:enzymology*; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009893:Opossums; D011480:Protease Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D020836:Protein Structure, Quaternary; D017386:Sequence Homology, Amino Acid
D001798:Blood Proteins; D003435:Crotalid Venoms; C454462:DM43 protein, Didelphis marsupialis; D011480:Protease Inhibitors; D008666:Metalloendopeptidases