Gallacci Márcia, Oliveira Maristela, Dal Pai-Silva Maeli, Cavalcante Walter Luís Garrido, Spencer Patrick Jack
Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Rubião Júnior, Botucatu, CEP 18618-000, São Paulo, Brazil.
Exp Toxicol Pathol. 2006 Jan;57(3):239-45. doi: 10.1016/j.etp.2005.09.004. Epub 2005 Nov 15.
As a first step to investigate the structure-function relationship of bothropstoxin-I (BthTX-I), a myotoxin from Bothrops jararacussu snake venom, our group previously cloned a recombinant toxin (rBthTX-I) in Escherichia coli. The aim of this work was to characterize the biological activities of this rBthTX-I (1.0 microM) in both phrenic-diaphragm and extensor digitorum longus preparations in vitro, by means of myographic and morphologic techniques. Native BthTX-I (1.0 microM) was used as a standard. The influence of heparin (27.5 microg/ml) upon the biological activities of both toxins was also investigated. rBthTX-I had similar effects to the native toxin inducing blockage of both directly and indirectly evoked contractions in phrenic-diaphragm preparations, and muscle damage characterized by edema, round fibers, and cell areas devoid of myofibrils. Interestingly the paralyzing activity of rBthTX-I was slightly more potent than the native toxin. Heparin prevented paralyzing and myotoxic effects of both the native and recombinant toxins. This work shows that rBthTX-I was expressed in a fully active form, and presents a biological profile similar to the native toxin.
作为研究矛头蝮蛇毒素 -I（BthTX-I，一种来自巴西矛头蝮蛇毒液的肌毒素）结构 - 功能关系的第一步，我们小组之前在大肠杆菌中克隆了一种重组毒素（rBthTX-I）。这项工作的目的是通过肌动描记法和形态学技术，在体外膈 - 膈肌和趾长伸肌标本中表征这种rBthTX-I（1.0微摩尔）的生物活性。天然BthTX-I（1.0微摩尔）用作标准。还研究了肝素（27.5微克/毫升）对两种毒素生物活性的影响。rBthTX-I对天然毒素具有类似的作用，可诱导膈 - 膈肌标本中直接和间接诱发的收缩阻滞，以及以水肿、圆形纤维和无肌原纤维的细胞区域为特征的肌肉损伤。有趣的是，rBthTX-I的麻痹活性比天然毒素略强。肝素可预防天然毒素和重组毒素的麻痹和肌毒性作用。这项工作表明，rBthTX-I以完全活性形式表达，并且呈现出与天然毒素相似的生物学特征。
