Studies on the role of the metK gene product of Escherichia coli K‐12
Studies on the role of the metK gene product of Escherichia coli K‐12
复制标题
大肠杆菌K-12metK基因产物的作用研究
作者：
Yuhong Wei;E. Newman
我们在这里表明，metK基因对大肠杆菌K‐12的生长至关重要，并且只有在携带功能性metK基因的拯救质粒存在时才能被删除。当metK表达受限时，基因组DNA甲基化降低，细胞分裂受阻。通过引物延伸，metK的转录起始位点位于翻译起始位点上游140bp处。常用的metK84突变体已被证明在metK启动子的−10区域携带A(r)G跃迁。这是其S -腺苷蛋氨酸（SAM）合成酶水平低和SAM缺乏的原因。
We show here that the metK gene is essential to the growth of Escherichia coli K‐12 and can be deleted only in the presence of a rescue plasmid carrying a functional metK gene. When metK expression was limited, genomic DNA methylation decreased and cell division was hampered. Through primer extension, the transcription start site of metK was located at 140 bp upstream of the translation start site. The frequently used metK84 mutant has been shown to carry an A(r)G transition in the −10 region of the metK promoter. This accounts for its low level of S‐adenosylmethionine (SAM) synthetase and SAM deficiency.