Solution structure of Escherichia coli PapI, a key regulator of the pap pili phase variation.
Solution structure of Escherichia coli PapI, a key regulator of the pap pili phase variation.
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大肠杆菌 PapI 的溶液结构，它是乳头菌毛相位变化的关键调节因子。
DOI：
10.1016/j.jmb.2006.10.066
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发表时间：
2007
影响因子：
5.6
通讯作者：
Dahlquist,FrederickW
中科院分区：
文献类型：
--
作者：
Kawamura,Tetsuya;Le,LisaUyenK;Zhou,Hongjun;Dahlquist,FrederickW
肾盂肾炎相关菌毛(PAP)使致尿路感染的大肠埃希菌与上皮细胞结合，在尿路感染中发挥重要作用。PAP的表达受一种阶段变化机制的控制，该机制基于两种不同的可遗传状态，这两种状态是其调节区中两个GATC序列中的任何一个的腺嘌呤N6甲基化的结果。这两个序列的甲基化状态是通过LRP和PAPI这两个蛋白质的作用来检测的，它们在决定PAP基因在阶段开启和阶段关闭细胞中的表达方面发挥着核心作用。我们用现代核磁共振技术测定了PAPI的溶液结构和主链动力学。我们发现它的整体折叠与DNA结合蛋白的有翼螺旋-转弯-螺旋家族非常相似。我们确定PAPI具有自己的DNA结合活性，虽然不是序列特异性的，但不依赖于LRP。PAPI似乎与10μM范围内的Kdin结合。根据这些新发现，讨论了PAPI可能参与纸操纵子调控的可能机制。
Pyelonephritis-associated pili (pap) allow uropathogenic Escherichia coli to bind to epithelial cells and play an important role in urinary tract infection. Expression of pap is controlled by a phase-variation mechanism, based on the two distinct heritable states that are the result of adenine N6-methylation in either of the two GATC sequences in its regulatory region. The methylation status of these two sequences is sensed by the action of two proteins, Lrp and PapI, and they play a central role in determining pap gene expression in both phase-ON and phase-OFF cells. We used modern NMR techniques to determine the solution structure and backbone dynamics of PapI. We found its overall fold resembles closely that of the winged helix-turn-helix family of DNA-binding proteins. We determined that PapI possesses its own DNA-binding activity, albeit non-sequence-specific, independent of Lrp. PapI appears to bind to DNA with a Kdin the 10 μM range. Possible mechanisms by which PapI might participate in the regulation of the pap operon are discussed in light of these new findings.