Au L C, Huang Y B, Huang T F, Teh G W, Lin H H, Choo K B
Department of Medical Research, Veterans General Hospital, Taipei, Taiwan, Republic of China.
Biochem Biophys Res Commun. 1991 Dec 16;181(2):585-93. doi: 10.1016/0006-291x(91)91230-a.
Rhodostomin is a platelet aggregation inhibitor secreted by the venom gland of Calloselasma rhodostoma. We report here the isolation of a 1.67-kilobase (kb) lambda gt11 cDNA clone using degenerate oligonucleotide probe based on a partial amino acid sequence of rhodostomin. The amino acid sequence deduced from an open reading frame of the cDNA indicates that (i) the 68-amino acid sequence of rhodostomin is located at the carboxyl terminus of the precursor polypeptide and (ii) a peroxisomal targeting sequence (ser.his.ala.) exists between the stop codon and the rhodostomin sequence of the precursor. Since the amino-terminal segment of the deduced sequence shows a high degree of identity with hemorrhagic proteins, which are zinc-metalloproteinases, found in the venom of some crotalid and viperid snakes, our results also predict the existence of at least one such hemorrhagic protein in the venom of Calloselasma rhodostoma. The derivation of a platelet aggregation inhibitor and a hemorrhagic protein from the same precursor protein is consistent with the fact that these proteins may be synergistic in function.
罗豆素是一种由圆斑蝰蛇毒腺分泌的血小板聚集抑制剂。我们在此报告，基于罗豆素的部分氨基酸序列，使用简并寡核苷酸探针分离出一个1.67千碱基（kb）的λgt11 cDNA克隆。从该cDNA的开放阅读框推导的氨基酸序列表明：（i）罗豆素的68个氨基酸序列位于前体多肽的羧基末端；（ii）在前体的终止密码子和罗豆素序列之间存在一个过氧化物酶体靶向序列（丝氨酸.组氨酸.丙氨酸）。由于推导序列的氨基末端片段与在一些蝰蛇科和蝰蛇科蛇毒中发现的出血性蛋白（锌金属蛋白酶）具有高度同一性，我们的结果还预测圆斑蝰蛇毒中至少存在一种此类出血性蛋白。从同一前体蛋白衍生出血小板聚集抑制剂和出血性蛋白，这与这些蛋白在功能上可能具有协同作用的事实是一致的。
