Joseph Pascale, Ratnayake-Lecamwasam Manoja, Sonenshein Abraham L
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA.
J Bacteriol. 2005 Jun;187(12):4127-39. doi: 10.1128/JB.187.12.4127-4139.2005.
Bacillus subtilis CodY protein is the best-studied member of a novel family of global transcriptional regulators found ubiquitously in low-G+C gram-positive bacteria. As for many DNA-binding proteins, CodY appears to have a helix-turn-helix (HTH) motif thought to be critical for interaction with DNA. This putative HTH motif was found to be highly conserved in the CodY homologs. Site-directed mutagenesis was used to identify amino acids within this motif that are important for DNA recognition and binding. The effects of each mutation on DNA binding in vitro and on the regulation of transcription in vivo from two target promoters were tested. Each of the mutations had similar effects on binding to the two promoters in vitro, but some mutations had differential effects in vivo.
枯草芽孢杆菌CodY蛋白是在低G+C革兰氏阳性细菌中普遍存在的一类新型全局转录调节因子家族中研究最为深入的成员。与许多DNA结合蛋白一样，CodY似乎具有一个螺旋-转角-螺旋（HTH）基序，据认为该基序对于与DNA的相互作用至关重要。已发现该推定的HTH基序在CodY同源物中高度保守。采用定点诱变来鉴定该基序内对DNA识别和结合很重要的氨基酸。测试了每个突变对体外DNA结合以及对来自两个靶启动子的体内转录调控的影响。每个突变在体外对与两个启动子的结合具有相似的影响，但有些突变在体内具有不同的影响。
