Benson N, Youderian P
Department of Biological Sciences, University of Southern California, Los Angeles 90089-1481.
Genetics. 1989 Jan;121(1):5-12. doi: 10.1093/genetics/121.1.5.
By assaying the binding of wild-type Cro to a set of 40 mutant lambda operators in vivo, we have determined that the 14 outermost base pairs of the 17 base pair, consensus lambda operator are critical for Cro binding. Cro protein recognizes 4 base pairs in a lambda operator half-site in different ways than cI repressor. The sequence determinants of Cro binding at these critical positions in vivo are nearly perfectly consistent with the model proposed by W. F. ANDERSON, D. H. OHLENDORF, Y. TAKEDA and B. W. MATTHEWS and modified by Y. TAKEDA, A. SARAI and V. M. RIVERA for the specific interactions between Cro and its operator, and explain the relative order of affinities of the six natural lambda operators for Cro. Our data call into question the idea that lambda repressor and Cro protein recognize the consensus lambda operator by nearly identical patterns of specific interactions.
通过在体内检测野生型Cro与一组40个突变λ操纵基因的结合,我们确定了17个碱基对的共有λ操纵基因中最外侧的14个碱基对对于Cro结合至关重要。Cro蛋白识别λ操纵基因半位点中的4个碱基对,其方式与cI阻遏蛋白不同。在体内这些关键位置上Cro结合的序列决定因素与W.F.安德森、D.H.奥伦多夫、Y.武田和B.W.马修斯提出并经Y.武田、A.萨赖和V.M.里韦拉修改的关于Cro与其操纵基因之间特异性相互作用的模型几乎完全一致,并解释了六个天然λ操纵基因对Cro亲和力的相对顺序。我们的数据对λ阻遏蛋白和Cro蛋白通过几乎相同的特异性相互作用模式识别共有λ操纵基因这一观点提出了质疑。