Ohlendorf D H, Anderson W F, Matthews B W
J Mol Evol. 1983;19(2):109-14. doi: 10.1007/BF02300748.
Amino acid and DNA sequence comparisons suggest that many sequence-specific DNA-binding proteins have in common an homologous region of about 22 amino acids. This region corresponds to two consecutive alpha-helices that occur in both Cro and cI repressor proteins of bacteriophage lambda and in catabolite gene activator protein of Escherichia coli and are presumed to interact with DNA. The results obtained here suggest that this alpha-helical DNA-binding fold occurs in many proteins that regulate gene expression. It also appears that this DNA-binding unit evolved from a common evolutionary precursor.
氨基酸和DNA序列比较表明，许多序列特异性DNA结合蛋白共有一个约22个氨基酸的同源区域。该区域对应于噬菌体λ的Cro和cI阻遏蛋白以及大肠杆菌的分解代谢基因激活蛋白中出现的两个连续的α螺旋，推测它们与DNA相互作用。此处获得的结果表明，这种α螺旋DNA结合结构域存在于许多调节基因表达的蛋白质中。此外，这种DNA结合单元似乎起源于一个共同的进化前体。
