科研之友
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摘要
Despite their isolation more than fifteen years ago from the venom of the African mamba Dendroaspis polylepis, very few data are known on the functional activity of MT beta and CM-3 toxins. MTO was initially classified as a muscarinic toxin interacting non-selectively and with low affinity with the five muscarinic receptor subtypes while no biological function was determined for CM-3. Recent results highlight the multifunctional activity of threefinger fold toxins for muscarinic and adrenergic receptors and reveal some discrepancies in the pharmacological profiles of their venom-purified and synthetic forms. Here, we report the pharmacological characterization of chemically-synthesized MT beta and CM-3 toxins on nine subtypes of muscarinic and adrenergic receptors and demonstrate their high potency for a-adrenoceptors and in particular a sub-nanomolar affinity for the OAsubtype. Strikingly, no or very weak affinity were found for muscarinic receptors, highlighting that pharmacological characterizations of venom-purified peptides may be risky due to possible contaminations. The biological profile of these two homologous toxins looks like that one previously reported for the Dendroaspis angusticeps p-Da1a toxin. Nevertheless, MT beta and CM-3 interact more potently than p-Dal a with alpha 1B- and al D-AR subtypes. A computational analysis of the stability of the MT beta tion.
- 出版日期2013-12-1
- 单位中国地震局
