Krizaj I, Liang N S, Pungercar J, Strukelj B, Ritonja A, Gubensek F
Department of Biochemistry, Jozef Stefan Institute, Ljubljana, Slovenia.
Eur J Biochem. 1992 Mar 15;204(3):1057-62. doi: 10.1111/j.1432-1033.1992.tb16728.x.
The amino acid sequence of a non-toxic phospholipase A2, ammodytin I2, from the venom of the long-nosed viper (Vipera ammodytes ammodytes) and its cDNA sequence have been determined. The protein sequence was elucidated by sequencing the peptides generated by CNBr cleavage, mild acid hydrolysis and tryptic digestion of maleylated and non-maleylated protein. Sequencing of the cDNA showed that the protein is synthesized as an 137-amino-acid-residue precursor molecule consisting of a 16-residue signal peptide, followed by a 121-residue mature enzyme. Ammodytin I2 cDNA shows 73% nucleotide and 59% amino acid identities in the mature protein region in comparison to that of ammodytoxin A, the most presynaptically neurotoxic phospholipase A2 from the long-nosed viper. Identities in the signal-peptide region are considerably higher, 96% and 100%, respectively.
已确定来自长吻蝰（Vipera ammodytes ammodytes）毒液的一种无毒磷脂酶A2——沙蝰毒素I2的氨基酸序列及其cDNA序列。通过对马来酰化和非马来酰化蛋白质经CNBr裂解、温和酸水解和胰蛋白酶消化产生的肽段进行测序，阐明了蛋白质序列。cDNA测序表明，该蛋白质作为一个由16个氨基酸残基的信号肽和随后121个氨基酸残基的成熟酶组成的137个氨基酸残基的前体分子合成。与长吻蝰中突触前神经毒性最强的磷脂酶A2——沙蝰毒素A相比，沙蝰毒素I2 cDNA在成熟蛋白区域的核苷酸同一性为73%，氨基酸同一性为59%。信号肽区域的同一性则高得多，分别为96%和100%。
