کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10798198 1053305 2005 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Inhibition of crotoxin binding to synaptosomes by a receptor-like protein from Crotalus durissus terrificus (the South American rattlesnake)
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Inhibition of crotoxin binding to synaptosomes by a receptor-like protein from Crotalus durissus terrificus (the South American rattlesnake)
چکیده انگلیسی
Crotoxin (Ctx) is a potent neurotoxin of the venom of Crotalus durissus terrificus (the South American rattlesnake). Ctx is a heterodimer composed of CB, a toxic PLA2 subunit, and CA, a non-toxic and non-enzymatic subunit, that potentiates the neurotoxicity of CB in vivo. The deleterious action of Ctx upon C. d. terrificus snakes themselves is known to be prevented by a PLA2 inhibitor (CNF) present in their blood serum. CNF acts by replacing CA in Ctx, thus forming a new stable complex CNF-CB. This complex no longer interacts with the target receptor (TR) to deliver CB to cause its lethal effect. Furthermore, CNF-CB seems to be reminiscent of the interaction Ctx-TR at the pre-synaptic site. In the present work, the binding competition between rat brain synaptosomes (TR) and CNF for Ctx was investigated. Radiolabeled Ctx, made of CA and one isoform of CB (CA-125ICB2), was used as ligand. The competition by unlabeled Ctx was taken as a reference. The potency of CNF as a competitor was evaluated under different incubation conditions with varying time scale addition of reagents (CA-125ICB2, synaptosomes and CA-CB2 or CNF). CNF was able to inhibit the binding of the toxin to synaptosomes as well as to partially displace the toxin already bound to its membrane target. The mechanisms of competition involved were discussed and a previous schematic model of interactions between Ctx, TR and CNF was updated.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1717, Issue 1, 10 November 2005, Pages 27-33
نویسندگان
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