Austin C A, Barot H A, Margerrison E E, Turcatti G, Wingfield P, Hayes M V, Fisher L M
Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, London, United Kingdom.
Biochem Biophys Res Commun. 1990 Jul 31;170(2):763-8. doi: 10.1016/0006-291x(90)92156-t.
The partial amino acid sequence of p140 calf thymus DNA topoisomerase II was determined by analysis of cyanogen bromide peptides. Five peptides were aligned and shared extensive homology with sequences derived from cDNA clones for the human topoisomerase II isoenzyme forms. Less homology was seen with the Drosophila, yeast and bacterial type II enzymes. Calf and human enzymes shared epitopes allowing isolation of a cDNA clone to human topoisomerase II isoenzyme alpha. Our results indicate that calf thymus p140 topoisomerase II is an active N-terminal proteolytic fragment of the native p180 enzyme and demonstrate that mammalian type II enzymes exhibit close sequence similarity.
通过对溴化氰肽段的分析，确定了小牛胸腺DNA拓扑异构酶II的部分氨基酸序列。比对了五个肽段，发现它们与人类拓扑异构酶II同工酶形式的cDNA克隆序列具有广泛的同源性。与果蝇、酵母和细菌的II型酶的同源性较低。小牛和人类的酶具有共同表位，可用于分离人类拓扑异构酶II同工酶α的cDNA克隆。我们的结果表明，小牛胸腺p140拓扑异构酶II是天然p180酶的活性N端蛋白水解片段，并证明哺乳动物II型酶具有密切的序列相似性。
