Blattner F R, Burland V, Plunkett G, Sofia H J, Daniels D L
Laboratory of Genetics, University of Wisconsin, Madison 53706.
Nucleic Acids Res. 1993 Nov 25;21(23):5408-17. doi: 10.1093/nar/21.23.5408.
We present the sequence of 176 kilobases of the Escherichia coli K-12 genome, from katG at 89.2 to an open reading frame (ORF) of unknown function at 92.8 minutes on the genetic map. This brings the total of contiguous sequence from the E. coli genome project to 500 kb (81.5 to 92.8 minutes). This segment contains 134 putative coding genes (ORFs) of which 66 genes were previously identified. Eight new genes--acs, pepE, and nrfB-G--were identified as well as the previously mapped gldA and alr genes. Still, 58 ORFs remain unidentified despite literature and similarity searches. The arrangement of proposed genes relative to possible promoters and terminators suggests 55 potential transcription units. Other features include 13 REP elements, one IRU (ERIC) repeat, 59 computer-predicted bends, 42 Chi sites and one new grey hole. Sixteen signal peptides were found, including those of lamB, btuB, and malE. Two ribosomal RNA loci, rrnB and rrnE, are located in this segment, so we have now sequenced four of the seven E. coli rRNA loci. Comparison of the rRNA loci reveals some differences in the ribosomal structural RNAs which are generally compatible with the proposed secondary structures.
我们展示了大肠杆菌K-12基因组176千碱基的序列，从遗传图谱上89.2分钟处的katG基因到92.8分钟处一个功能未知的开放阅读框（ORF）。这使得大肠杆菌基因组计划的连续序列总数达到500 kb（81.5至92.8分钟）。该片段包含134个推定的编码基因（ORF），其中66个基因先前已被鉴定。我们鉴定出了8个新基因——acs、pepE和nrfB - G，以及先前已定位的gldA和alr基因。尽管进行了文献检索和相似性搜索，仍有58个ORF未被鉴定。所提议基因相对于可能的启动子和终止子的排列表明有55个潜在的转录单元。其他特征包括13个REP元件、1个IRU（ERIC）重复序列、59个计算机预测的弯曲、42个Chi位点和1个新的灰洞。发现了16个信号肽，包括lamB、btuB和malE的信号肽。两个核糖体RNA位点rrnB和rrnE位于该片段中，因此我们现在已经对大肠杆菌7个rRNA位点中的4个进行了测序。rRNA位点的比较揭示了核糖体结构RNA中的一些差异，这些差异总体上与所提议的二级结构相符。
