Kräusslich H G, Von der Helm K
Virology. 1987 Feb;156(2):246-52. doi: 10.1016/0042-6822(87)90404-1.
The proteolytic processing of the gag precursor polypeptide pr65gag of simian sarcoma-associated virus (SSAV) has been studied in vivo and in vitro. In SSAV-infected cells (i.e., in vivo) proteins of 52 and 38 kDa and the viral protein p30 could be immunoprecipitated with anti-p30 serum. This cleavage pattern is only in part imitated by in vitro cleavage of the isolated pr65gag with avian myeloblastosis virus (AMV) protease p15. However, in vitro incubation of isolated pr65gag with detergent-disrupted SSAV particles generated products identical in size to those found in vivo, i.e., proteins of 52 and 38 kDa and p30. The extent of cleavage is dependent on the concentration of the disrupted virions added to the incubation mixture. Studies with protease inhibitors suggest that the SSAV enzyme is a serine-type protease like that of other mammalian retroviruses and unlike the protease of avian viruses. The SSAV protease activity eluted from a molecular sieve column in a range of about 10-15 kDa reflecting the molecular weight of the murine leukemia virus (MuLV) protease (Mr = 13.5K). Thus, it appears that there is a close similarity between the proteolytic enzymes present in different mammalian retroviruses such as MuLV and SSAV.
对猿猴肉瘤相关病毒（SSAV）的gag前体多肽pr65gag的蛋白水解加工过程进行了体内和体外研究。在SSAV感染的细胞中（即体内），52 kDa和38 kDa的蛋白以及病毒蛋白p30可用抗p30血清进行免疫沉淀。这种切割模式仅部分被用禽成髓细胞瘤病毒（AMV）蛋白酶p15对分离的pr65gag进行的体外切割所模仿。然而，将分离的pr65gag与经去污剂处理破坏的SSAV颗粒进行体外孵育，产生的产物在大小上与体内发现的产物相同，即52 kDa和38 kDa的蛋白以及p30。切割程度取决于添加到孵育混合物中的经破坏的病毒粒子的浓度。蛋白酶抑制剂研究表明，SSAV酶是一种丝氨酸型蛋白酶，与其他哺乳动物逆转录病毒的蛋白酶类似，与禽病毒的蛋白酶不同。从分子筛柱上洗脱的SSAV蛋白酶活性在约10 - 15 kDa范围内，这反映了鼠白血病病毒（MuLV）蛋白酶的分子量（Mr = 13.5K）。因此，不同的哺乳动物逆转录病毒如MuLV和SSAV中存在的蛋白水解酶之间似乎有密切的相似性。
