PROCARYOTIC AND EUKARYOTIC TRAITS OF DNA METHYLATION IN SPIROPLASMAS (MYCOPLASMAS)
PROCARYOTIC AND EUKARYOTIC TRAITS OF DNA METHYLATION IN SPIROPLASMAS (MYCOPLASMAS)
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DOI：
10.1128/jb.164.1.19-24.1985
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发表时间：
1985-01-01
影响因子：
3.2
通讯作者：
RAZIN, S
中科院分区：
文献类型：
--
作者：
NUR, I;SZYF, M;RAZIN, S
用高压液相色谱检测五种螺旋体DNA中碱基甲基化类型(胞嘧啶或腺嘌呤)和甲基化程度的差异。最近邻分析和限制性内切酶同裂体消化也显示甲基化序列特异性的差异。而在花瓣螺旋体和螺旋体中。菌株PPS-1的5-甲基胞嘧啶存在于4个主要碱基的5‘’侧，而API螺旋体DNA中的胞嘧啶只有在其3‘’端的碱基为腺嘌呤或胸腺嘧啶时才发生甲基化。在Spriodium sp.中，MQ-1菌株95%以上的甲基化胞嘧啶为C-G序列。基本上，MQ-1DNA中的所有C-G序列都是甲基化的。部分纯化的蜜蜂螺旋体和螺旋体提取物。以菌株MQ-1为研究对象，研究了该甲基酶的底物和序列特异性。MQ-1酶的甲基化仅发生在C-G序列上，在这方面与真核DNA甲基酶相似。然而，MQ-1甲基酶与真核生物甲基酶的不同之处在于，MQ-1甲基酶在非甲基化的DNA双链上活性高，在半甲基化的DNA双链上活性低，在单链DNA上没有活性。
Differences in the type of base methylated (cytosine or adenine) and in the extent of methylation were detected by high-pressure liquid chromatography in the DNAs of five spiroplasmas. Nearest neighbor analysis and digestion by restriction enzyme isoschizomers also revealed differences in methylation sequence specificity. Whereas in Spiroplasma floricola and Spiroplasma sp. strain PPS-1 5-methylcytosine was found on the 5'' side of each of the four major bases, the cytosine in Spiroplasma apis DNA was methylated only when its 3'' neighboring base was adenine or thymine. In Sprioplasma sp. strain MQ-1 over 95% of the methylated cytosine was in C-G sequences. Essentially all of the C-G sequences in the MQ-1 DNA were methylated. Partially purified extracts of S. apis and Spiroplasma sp. strain MQ-1 were used to study substrate and sequence specificity of the methylase activity. Methylation by the MQ-1 enzyme was exclusively at C-G sequences, resembling in this respect eucaryotic DNA methylases. However, the MQ-1 methylase differed from eucaryotic methylases by showing high activity on nonmethylated DNA duplexes, low activity with hemimethylated DNA duplexes, and no activity on single-stranded DNA.