Isolation of a Disintegrin from the Venom of Crotalus atrox (Western Diamondback Rattlesnake)

Jacob A. Galán¹, Angelica M. García¹, Elda E. Sánchez^1,2, Luis M. Salgueiro-Tosta^1,2, Alexis Rodríguez-Acosta² and John C. Pérez¹

1 Natural Toxins Research Center (NTRC), Texas A&M University-Kingsville,

MSC 158, Kingsville, TX 78363, 2 Universidad Central de Venezuela, Instituto de Medicina Tropical, Sección de Inmunoquímica, Caracas 1041, Venezuela

The disintegrins are a group of proteins found in snake venoms, which are classified as non-enzymatic proteins. Disintegrins are naturally occurring proteins found in the Viperidae family of snakes. In this study, a disintegrin from the venom of Crotalusatrox was isolated and characterized. Disintegrins exist in two forms, a monomeric form and a dimeric form.  The monomeric disintegrins are low molecular weight molecules 4-10 kDa, and dimeric disintegrins are 21 kDa.   All monomeric forms possess K/RGD at the tip of a loop.  Dimeric forms contain MLD, MGD, VGD, KGD, and RGD.  The dimeric forms generally exist as heterodimers.  Many isolated disintegrins show a homology with one another, particularly in the cysteine arrangement.  A monomeric disintegrin has been isolated from Crotalusatrox venom by methanol precipitation and reverse phase C18 chromatography. The calculated pI was 4.76 and the molecular mass was determined to be 7.4 kDa by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The disintegrin inhibits ADP induced platelet aggregation and platelet retraction in whole blood.  The disintegrin was unable to inhibit the binding of human urinary bladder carcinoma cells (T24) to fibronectin suggesting a specific affinity to the a_IIbb3 integrin than that of the avb5 and avb3 integrins found on T24 cells.

Correspondence to: elda.sanchez@tamuk.edu