Firshein W, Gelman I W
Mol Gen Genet. 1981;182(1):87-94. doi: 10.1007/BF00422772.
Three DNA polymerase activities, one related to DNA pol III, have been extracted from a DNA membrane complex purified from Streptococcus pneumoniae. DNA pol III was purified 3300-fold, DNA pol II 2800-fold and DNA pol I 1800-fold. Based on inhibition analysis with a drug known to inhibit DNA pol III activity in Gram positive organisms. 6(p-hydroxyphenyl azo) uracil (HpU), 55% of the total DNA polymerase activity is represented by pol III. In contrast, only 3-5% of the total DNA polymerase activity is inhibited by HpU in crude extracts. The purification of the DNA membrane complex from pneumococcus is modified from an earlier procedure (Firshein 1972). The modified procedure results in the separation of three distinct DNA-protein-phospholipid subcomplexes of which the one described above contains most of the radioactivity derived from cells pulsed for a short time with (3H)-thymidine. Proteins are involved in binding DNA in each complex and the conformation of DNA in each complex may be different. All of the subcomplexes contain DNA polymerase activity partially sensitive to HpU. These results provide direct evidence for the structural integrity of a complex that may be involved in DNA replication in vivo.
已从肺炎链球菌纯化的DNA膜复合物中提取出三种DNA聚合酶活性，其中一种与DNA聚合酶III相关。DNA聚合酶III纯化了3300倍，DNA聚合酶II纯化了2800倍，DNA聚合酶I纯化了1800倍。基于用一种已知可抑制革兰氏阳性菌中DNA聚合酶III活性的药物进行的抑制分析。6（对羟基苯基偶氮）尿嘧啶（HpU），总DNA聚合酶活性的55%由聚合酶III代表。相比之下，粗提物中只有3-5%的总DNA聚合酶活性被HpU抑制。从肺炎球菌中纯化DNA膜复合物的方法是对早期方法（Firshein 1972）进行的改进。改进后的方法导致分离出三种不同的DNA-蛋白质-磷脂亚复合物，其中上述亚复合物含有大部分源自用（3H）-胸苷短时间脉冲处理的细胞的放射性。蛋白质参与每个复合物中DNA的结合，并且每个复合物中DNA的构象可能不同。所有亚复合物都含有对HpU部分敏感的DNA聚合酶活性。这些结果为一种可能参与体内DNA复制的复合物的结构完整性提供了直接证据。
