Stankevicius K, Povilionis P, Lubys A, Menkevicius S, Janulaitis A
Institute of Biotechnology FERMENTAS, Vilnius, Lithuania.
Gene. 1995 May 19;157(1-2):49-53. doi: 10.1016/0378-1119(94)00796-u.
An Escherichia coli RFL47 DNA fragment containing the Eco47IR and Eco47II restriction-modification (R-M) system has been cloned and sequenced. A clone carrying this system has been selected by its ability to restrict phage lambda in vivo. The sequence of 5360 bp was determined, and its analysis revealed three major open reading frames (ORF) corresponding to two restriction endonucleases (ENases) and one DNA methyltransferase (MTase): R.Eco47II (239 amino acid (aa)), R.Eco47I (230 aa) and M.Eco47II (417 aa). The M.Eco47II aa sequence possesses all conserved domains typical for m5C MTases and its variable region has a high homology with M.Sau96I and M.SinI. The ORF harboring a predicted helix-turn-helix motif upstream from the eco47IR gene has been found. No sequence resembling the eco47IM gene has been detected in the complete fragment sequenced, although disrupted ORF, possibly corresponding to the transposase-encoding gene, has been found in the intergenic area between eco47IIM and eco47IR. No homology was found between the ENases; however, both revealed homology with their isoschizomers, R.SinI and R.Sau96I.
一个包含Eco47IR和Eco47II限制修饰（R-M）系统的大肠杆菌RFL47 DNA片段已被克隆并测序。通过其在体内限制噬菌体λ的能力筛选出了携带该系统的克隆。测定了5360 bp的序列，分析显示有三个主要的开放阅读框（ORF），分别对应两种限制性内切酶（ENase）和一种DNA甲基转移酶（MTase）：R.Eco47II（239个氨基酸（aa））、R.Eco47I（230个aa）和M.Eco47II（417个aa）。M.Eco47II的氨基酸序列具有m5C MTase典型的所有保守结构域，其可变区与M.Sau96I和M.SinI具有高度同源性。在eco47IR基因上游发现了一个含有预测的螺旋-转角-螺旋基序的ORF。在测序的完整片段中未检测到与eco47IM基因相似的序列，尽管在eco47IIM和eco47IR之间的基因间隔区发现了可能对应于转座酶编码基因的 disrupted ORF。两种ENase之间未发现同源性；然而，它们都与其同裂酶R.SinI和R.Sau96I显示出同源性。
