The mutL repair gene of Escherichia coli K-12 forms a superoperon with a gene encoding a new cell-wall amidase.
The mutL repair gene of Escherichia coli K-12 forms a superoperon with a gene encoding a new cell-wall amidase.
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大肠杆菌 K-12 的 mutL 修复基因与编码新细胞壁酰胺酶的基因形成超级操纵子。
DOI：
10.1111/j.1365-2958.1994.tb00300.x
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发表时间：
1994
影响因子：
3.6
通讯作者：
Winkler,ME
中科院分区：
文献类型：
--
作者：
Tsui,HC;Zhao,G;Feng,G;Leung,HC;Winkler,ME
We report a molecular genetic analysis of the region Immediately upstream from theEscherichia coli mutLDNA repair gene at 94.8 min. An open reading frame ending 9bp upstream from the start ofmutLcorresponds to a 48kDa polypeptide detected previously in minicells. The predicted amino acid sequence of this 48kDa polypeptide shows homology to the major N‐acetylmuramoyl‐L‐alanine amidase autolysin ofBacillus subtilis, a known amidase ofBacillus licheniformis, and the product of aSalmonella typhimuriumgene that maps near SO min. Insertions in this upstream gene, which we namedAmiB, or inmutLdid not affect cell shape or viability; however, overexpression of the AmiB potypeptide caused ceil lysis, hypersensitivity to osmotic shock and treatment with water, and temporary autolysis by low levels of antibiotics, which are all consistent with AmiB acting as a cell‐wall hydrolase. Analysis of chromosomal transcription demonstrated thatamiBforms a complex operon withmutLand two additional upstream genes.mutLtranscripts also originated from an internal promoter, designated PmutL, located inamiB312bp upstream from the translational start ofmutL.Together, these results suggest thatE. colicontains a second amidase possibly involved in cell‐wall hydrolysis, septation, or recycling, and that transcription of this amidase is directly linked to a gene central for DNA repair.
