Olsen L C, Aasland R, Wittwer C U, Krokan H E, Helland D E
Laboratory of Biotechnology, University of Bergen, Norway.
EMBO J. 1989 Oct;8(10):3121-5. doi: 10.1002/j.1460-2075.1989.tb08464.x.
Uracil-DNA glycosylase is the DNA repair enzyme responsible for the removal of uracil from DNA, and it is present in all organisms investigated. Here we report on the cloning and sequencing of a cDNA encoding the human uracil-DNA glycosylase. The sequences of uracil-DNA glycosylases from yeast, Escherichia coli, herpes simplex virus type 1 and 2, and homologous genes from varicella-zoster and Epstein-Barr viruses are known. It is shown in this report that the predicted amino acid sequence of the human uracil-DNA glycosylase shows a striking similarity to the other uracil-DNA glycosylases, ranging from 40.3 to 55.7% identical residues. The proteins of human and bacterial origin were unexpectedly found to be most closely related, 73.3% similarity when conservative amino acid substitutions were included. The similarity between the different uracil-DNA glycosylase genes is confined to several discrete boxes. These findings strongly indicate that uracil-DNA glycosylases from phylogenetically distant species are highly conserved.
尿嘧啶-DNA糖基化酶是一种负责从DNA中去除尿嘧啶的DNA修复酶，在所有被研究的生物体中都存在。在此我们报告编码人尿嘧啶-DNA糖基化酶的cDNA的克隆和测序。酵母、大肠杆菌、单纯疱疹病毒1型和2型的尿嘧啶-DNA糖基化酶序列，以及水痘-带状疱疹病毒和爱泼斯坦-巴尔病毒的同源基因序列均已为人所知。本报告显示，人尿嘧啶-DNA糖基化酶的预测氨基酸序列与其他尿嘧啶-DNA糖基化酶具有显著相似性，相同残基的比例在40.3%至55.7%之间。出人意料的是，发现人和细菌来源的蛋白质关系最为密切，若包括保守氨基酸替换，相似性为73.3%。不同尿嘧啶-DNA糖基化酶基因之间的相似性局限于几个离散的区域。这些发现有力地表明，系统发育上距离遥远的物种的尿嘧啶-DNA糖基化酶高度保守。
