Perez L G, Hunter E
J Virol. 1987 May;61(5):1609-14. doi: 10.1128/JVI.61.5.1609-1614.1987.
We have investigated the specificity of the proteolytic cleavage of the Rous sarcoma virus glycoprotein precursor by introducing two mutations into the putative cleavage region (Arg-Arg-Lys-Arg). We show that neither a deletion of the cleavage sequence nor a glutamic acid for lysine substitution altered intracellular transport or surface expression of the env gene products. However, both the four-amino-acid deletion and the glutamic acid substitution block processing of the env precursor. Susceptibility of the glutamic acid-substituted env precursor to proteases indicated that tertiary protein structure was unaffected. While inhibitor experiments suggested that more than one endopeptidase might be capable of mediating the proteolytic cleavage, the results presented here point to the presence in the Golgi apparatus of a novel endopeptidase, required for retroviral glycoprotein cleavage, that has a high specificity for lysine-containing peptides.
我们通过在假定的裂解区域（精氨酸-精氨酸-赖氨酸-精氨酸）引入两个突变，研究了劳氏肉瘤病毒糖蛋白前体蛋白水解裂解的特异性。我们发现，裂解序列的缺失或赖氨酸被谷氨酸取代均未改变env基因产物的细胞内运输或表面表达。然而，四氨基酸缺失和谷氨酸取代均阻断了env前体的加工。谷氨酸取代的env前体对蛋白酶的敏感性表明蛋白质三级结构未受影响。虽然抑制剂实验表明可能不止一种内肽酶能够介导蛋白水解裂解，但此处给出的结果表明，高尔基体中存在一种新型内肽酶，它是逆转录病毒糖蛋白裂解所必需的，对含赖氨酸的肽具有高度特异性。
