Yoshinaka Y, Shames R, Luftig R B
J Gen Virol. 1983 Jan;64 (Pt 1):95-102. doi: 10.1099/0022-1317-64-1-95.
We have recently found that, in vitro, the murine leukaemia virus (MuLV)-associated protein kinase activity predominantly phosphorylates Pr65gag, a virus protein present in relatively small amounts in partially purified virus preparations. Other virus proteins, such as p10, Pr27gag and Pr40gag, are also phosphorylated in vitro, but to a lesser degree. Furthermore, when immature core subparticles which are enriched in Pr65gag are prepared from virions by Sepharose 6B exclusion column chromatography, about 50% of the kinase activity (as assayed with the exogenous substrate phosvitin) remains associated with the cores. We report here that this core-associated activity is distinct from Pr65gag since it can be separated from Pr65gag by chromatography on denatured DNA--cellulose columns followed by centrifugation of the 0.2 M-NaCl-eluted fraction. Under these conditions, Pr65gag is pelleted while the kinase activity, which can phosphorylate both endogenous (MuLV Pr65gag and p10) as well as exogenous (phosvitin) substrates, remains in the supernatant. Interestingly, when the amount of Pr65gag is reduced, as in such preparations, p10 then becomes more heavily phosphorylated.
我们最近发现，在体外，鼠白血病病毒（MuLV）相关的蛋白激酶活性主要使Pr65gag磷酸化，Pr65gag是一种在部分纯化的病毒制剂中含量相对较少的病毒蛋白。其他病毒蛋白，如p10、Pr27gag和Pr40gag，在体外也会被磷酸化，但程度较低。此外，当通过琼脂糖6B排阻柱色谱从病毒粒子中制备富含Pr65gag的未成熟核心亚颗粒时，约50%的激酶活性（以外源底物卵黄高磷蛋白检测）仍与核心相关。我们在此报告，这种与核心相关的活性与Pr65gag不同，因为它可以通过在变性DNA-纤维素柱上进行色谱分离，然后对0.2M NaCl洗脱级分进行离心，从而与Pr65gag分离。在这些条件下，Pr65gag沉淀，而能够使内源性（MuLV Pr65gag和p10）以及外源性（卵黄高磷蛋白）底物磷酸化的激酶活性仍留在上清液中。有趣的是，在这样的制剂中，当Pr65gag的量减少时，p10随后会被更大量地磷酸化。
