Hirata Y, Yoshimi H, Marumo F, Watanabe T X, Kumagaye S, Nakajima K, Kimura T, Sakakibara S
Department of Medicine, Tokyo Medical and Dental University, Japan.
Biochem Biophys Res Commun. 1989 Jul 14;162(1):441-7. doi: 10.1016/0006-291x(89)92017-2.
The effects of synthetic analogs of sarafotoxin (STX) S6b, a snake venom peptide with a high sequence homology to the endothelium-derived vasoconstrictor endothelin (ET), on ET receptor binding activity and cytosolic free Ca2+ concentration [( Ca2+]i) were studied in cultured rat vascular smooth muscle cells. Binding studies revealed that [Cys1-15, Cys3-11] STX competed with 125I-ET for the binding to its vascular receptors with lower affinity than that of ET, but was far more effective than [Cys1-11, Cys3-15]STX in inhibiting the binding. [Cys1-15, Cys3-11]STX had a less potent effect on increasing [Ca2+]i than ET, whereas [Cys1-11, Cys3-15]STX was inactive. These data suggest that there may exist heterogenous subpopulations of the vascular ET/STX receptors, and that the proper double cyclic structure of STX is essential for interacting with its putative receptors to induce the [Ca2+]i response.
在培养的大鼠血管平滑肌细胞中，研究了与内皮素（ET）具有高度序列同源性的蛇毒肽——萨拉毒素（STX）S6b的合成类似物对ET受体结合活性和胞质游离钙离子浓度[Ca2+]i的影响。结合研究表明，[Cys1-15, Cys3-11] STX与125I-ET竞争结合其血管受体，其亲和力低于ET，但在抑制结合方面比[Cys1-11, Cys3-15] STX有效得多。[Cys1-15, Cys3-11] STX在增加[Ca2+]i方面的作用比ET弱，而[Cys1-11, Cys3-15] STX无活性。这些数据表明，血管ET/STX受体可能存在异质性亚群，并且STX适当的双环结构对于与其假定受体相互作用以诱导[Ca2+]i反应至关重要。
