Joyce C M, Kelley W S, Grindley N D
J Biol Chem. 1982 Feb 25;257(4):1958-64.
We report the nucleotide sequence of 3.2 kilobase pair region of the Escherichia coli polA gene, comprising the coding region for DNA polymerase I with about 400 base pairs of flanking sequence. The amino acid sequence for DNA polymerase I derived from our DNA sequence is largely consistent with previous protein chemical data. In the following paper, Brown et al. (Brown, W. E., Stump, K. H., and Kelley, W. S. (1982) J. Biol. Chem. 257, 1965-1972) present additional protein chemistry experiments that further confirm our sequence. Mild proteolysis of DNA polymerase I is known to produce two enzymatically active fragments (Brutlag, D., Atkinson, M. R., Setlow, P., and Kornberg, A. (1969) Biochem. Biophys. Res. Commun. 37, 982-989; Klenow, H., and Henningsen, I. (1970) Proc. Natl. Acad. Sci. U. S. A. 74, 5632-5636). We have located the site of this cleavage between residues 323 and 324 of the 928 amino acid polymerase molecule. By sequence comparison of the polA1 and wild type alleles, we have identified the polA1 mutation as a change from Trp (TGG) to amber (TAG) at residue 342.
我们报道了大肠杆菌polA基因3.2千碱基对区域的核苷酸序列，该区域包含DNA聚合酶I的编码区及约400个碱基对的侧翼序列。从我们的DNA序列推导得到的DNA聚合酶I的氨基酸序列与先前的蛋白质化学数据基本一致。在接下来的论文中，布朗等人（布朗，W. E.，斯顿普，K. H.，凯利，W. S.（1982年）《生物化学杂志》257卷，1965 - 1972页）进行了更多的蛋白质化学实验，进一步证实了我们的序列。已知对DNA聚合酶I进行温和的蛋白酶解会产生两个具有酶活性的片段（布鲁特拉格，D.，阿特金森，M. R.，塞特洛，P.，科恩伯格，A.（1969年）《生物化学与生物物理研究通讯》37卷，982 - 989页；克勒诺，H.，亨宁森，I.（1970年）《美国国家科学院院刊》74卷，5632 - 5636页）。我们已确定在928个氨基酸的聚合酶分子中，这种切割位点位于第323和324位残基之间。通过对polA1和野生型等位基因的序列比较，我们已确定polA1突变是第342位残基处从色氨酸（TGG）变为琥珀突变（TAG）。
