Conformational changes of Loxosceles venom sphingomyelinases monitored by circular dichroism.
Envenomation by arachnids of the genus Loxosceles can induce a variety of biological effects, including dermonecrosis and hemolysis. We have previously identified in L. intermedia venom two highly homologous proteins with sphingomyelinase activity, termed P1 and P2, responsible for all these pathological events, and also an inactive isoform P3. The toxins P1 and P2 displayed 85% identity with each other at the amino acid level and showed a 57% identity with SMase I, an active toxin from L. laeta venom. Circular dichroism was used to determine and compare the solution structure of the active and inactive isoforms. Effects of pH and temperature change on the CD spectra of the toxins were investigated and correlated with the biological activities. This study sheds new light on the structure-function relationship of homologous proteins with distinct biological properties and represents the first report on the structure-function relationship of Loxosceles sphingomyelinases D.
de Andrade
Sonia A
SA
Laboratório de Imunoquímica, Instituto Butantan, SP, Brazil.
Pedrosa
Matheus F Fernandes
MF
de Andrade
Rute M Gonçalves
RM
Oliva
Maria Luiza Vilela
ML
van den Berg
Carmen W
CW
Tambourgi
Denise V
DV
D000818:Animals; D001665:Binding Sites; D002942:Circular Dichroism; D006461:Hemolysis; D006863:Hydrogen-Ion Concentration; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D013108:Sphingomyelin Phosphodiesterase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013111:Spider Venoms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013112:Spiders / Q000201:enzymology / Q000235:genetics; D013696:Temperature
D020033:Protein Isoforms; D013111:Spider Venoms; C055161:loxosceles venom; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase