Lysine 188 of the catabolite gene activator protein (CAP) plays no role in specificity at base pair 7 of the DNA half site.
Lysine 188 of the catabolite gene activator protein (CAP) plays no role in specificity at base pair 7 of the DNA half site.
复制标题
分解代谢物基因激活蛋白 (CAP) 的赖氨酸 188 在 DNA 半位点第 7 碱基对的特异性中不发挥作用。
DOI：
10.1093/nar/18.6.1457
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发表时间：
1990
影响因子：
14.9
通讯作者：
Krakow,JS
中科院分区：
文献类型：
--
作者：
Ebright,RH;Gunasekera,A;Zhang,XP;Kunkel,TA;Krakow,JS
对于CAP-DNA复合物中的氨基酸-碱基对接触，已经提出了两个相似但不相同的模型（“模型I "，Weber，I.和Steitz，T.，Proc.Natl.Acad.Sci. USA，81，3973-3977，1984;“模型II”，Ebright等人，Proc.Natl.Acad.Sci. USA，81，7274-7278，1984）。两种模型之间最重要的区别在于CAP的Lys 188。模型I预测CAP的Lys 188与DNA半位点的碱基对7进行特异性决定接触。相反，模型II预测Lys 188不与DNA半位点的碱基对7接触。在目前的工作中，我们已经使用定点突变，以取代赖氨酸188的CAP由天冬酰胺，一个氨基酸不能使假定的接触。我们评估了以下蛋白质的特异性，无论是在体外还是在体内：野生型CAP，[Asn 188]CAP，[Val 181]CAP和[Val 181; Asn 188]CAP。结果表明，Lys 188对DNA半位点的碱基对7的特异性没有贡献。我们建议，相反的模型I，Lys 188不接触的DNA半位点的碱基对7。
Two similar, but not identical, models have been proposed for the amino acid-base pair contacts in the CAP-DNA complex (‘model I,’ Weber, I. and Steitz, T.,Proc.Natl.Acad.Sci. USA, 81, 3973–3977, 1984; ‘model II,’ Ebright,et al.,Proc.Natl.Acad.Sci. USA, 81, 7274–7278, 1984). The most important difference between the two models involves Lys188 of CAP. Model I predicts that Lys188 of CAP makes a specificity determining contact with base pair 7 of the DNA half site. In contrast, model II predicts that Lys188 makes no contact with base pair 7 of the DNA half site. In the present work, we have used site-directed mutagenesis to replace Lys188 of CAP by Asn, an amino acid unable to make the putative contact. We have assessed the specificities of the following proteins, bothin vitroandin vivo: wild-type CAP, [Asn188]CAP, [Val181]CAP and [Val181;Asn188]CAP. The results indicate that Lys188 makes no contribution to specificity at base pair 7 of the DNA half site. We propose, contrary to model I, that Lys188 makes no contact with base pair 7 of the DNA half site.