Vidal-Ingigliardi D, Richet E, Danot O, Raibaud O
Unité de Génétique Moléculaire, Centre National de la Recherche Scientifique, URA 1149, Institut Pasteur, Paris, France.
J Biol Chem. 1993 Nov 25;268(33):24527-30.
MalT, the transcriptional activator of the Escherichia coli maltose regulon, is a 901-amino acid-long protein that specifically binds to short, asymmetric nucleotide sequences present in several copies in the promoters of the regulon. We report that the protein structure involved in this specific binding is carried by a small C-terminal part of MalT encompassing the last 95 amino acid residues. This was demonstrated by fusing the last 95 codons of malT to the gene that encodes glutathione S-transferase, purifying the hybrid protein by affinity chromatography, and comparing the DNase I and dimethyl sulfate footprints of the hybrid and of wild-type MalT on different MalT-binding sites. MalT belongs to a large family of prokaryotic transcriptional activators, which share significant homology in their approximately 60-amino acid C-terminal regions. Our result strongly supports the suggestion that the region of homology corresponds to the DNA-binding domain of the proteins in this family.
MalT是大肠杆菌麦芽糖调节子的转录激活因子，是一种由901个氨基酸组成的蛋白质，它能特异性结合调节子启动子中多个拷贝存在的短的、不对称核苷酸序列。我们报道，参与这种特异性结合的蛋白质结构由MalT的一个小的C末端部分携带，该部分包含最后95个氨基酸残基。通过将malT的最后95个密码子与编码谷胱甘肽S-转移酶的基因融合，通过亲和层析纯化杂交蛋白，并比较杂交蛋白和野生型MalT在不同MalT结合位点上的DNase I和硫酸二甲酯足迹，证明了这一点。MalT属于一大类原核转录激活因子，它们在其大约60个氨基酸的C末端区域具有显著的同源性。我们的结果有力地支持了这样的推测，即同源区域对应于该家族中蛋白质的DNA结合结构域。
