Leis J P, Berkower I, Hurwitz J
Proc Natl Acad Sci U S A. 1973 Feb;70(2):466-70. doi: 10.1073/pnas.70.2.466.
Purified preparations of RNA-dependent DNA polymerase isolated from avain myeloblastosis virus contain RNase H activity. Labeled ribohomopolymers are degraded in the presence of their complementary deoxyribopolymer, except [(3)H]poly(U).poly(dA). The degradation products formed from [(3)H]poly(A).poly(dT) were identified as oligonucleotides containing 3'-hydroxyl and 5'-phosphate termini, while AMP was not detected. The nuclease has been characterized as a processive exonuclease that requires ends of poly(A) chains for activity. Exonucleolytic attack occurs in both 5' to 3' and 3' to 5' directions.RNase H has also been purified from E. coli. This nuclease degrades all homoribopolymers tested in the presence of their complementary deoxyribopolymers to yield oligonucleotides with 5'-phosphate and 3'-hydroxyl termini. E. coli RNase H has been characterized as an endonuclease.
从禽成髓细胞瘤病毒中分离得到的依赖RNA的DNA聚合酶的纯化制剂含有核糖核酸酶H活性。标记的核糖同聚物在其互补脱氧核糖聚合物存在的情况下会被降解,但[(3)H]聚(U)·聚(dA)除外。由[(3)H]聚(A)·聚(dT)形成的降解产物被鉴定为含有3'-羟基和5'-磷酸末端的寡核苷酸,而未检测到AMP。该核酸酶已被表征为一种连续性外切核酸酶,其活性需要聚(A)链的末端。外切核酸酶攻击在5'到3'和3'到5'两个方向上都有发生。核糖核酸酶H也已从大肠杆菌中纯化出来。这种核酸酶在其互补脱氧核糖聚合物存在的情况下会降解所有测试的核糖同聚物,产生具有5'-磷酸和3'-羟基末端的寡核苷酸。大肠杆菌核糖核酸酶H已被表征为一种内切核酸酶。