New roles for key residues in helices H1 and H2 of the Escherichia coli H-NSN-terminal domain:: H-NS dimer stabilization and Hha binding
New roles for key residues in helices H1 and H2 of the Escherichia coli H-NSN-terminal domain:: H-NS dimer stabilization and Hha binding
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DOI：
10.1016/j.jmb.2006.03.059
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发表时间：
2006-06-09
影响因子：
5.6
通讯作者：
Pons, Miquel
中科院分区：
文献类型：
--
作者：
Garcia, Jesus;Madrid, Cristina;Pons, Miquel
细菌核相关蛋白H-NS和Hha响应环境因素调节基因表达。H-NS的N末端结构域参与同聚体和异聚体蛋白质-蛋白质相互作用。同聚物的相互作用导致二聚体和更高级的低聚物的形成。与Hha样蛋白的异聚体相互作用改变了H-NS的调节特性。在这项研究中，我们已经使用NMR和诱变的N-末端结构域的H-NS，以确定Hha结合区域周围的螺旋H1和H2的H-NS。两个保守的精氨酸残基，R12和R15，位于螺旋H2的同一侧和相邻的转弯处，被证明参与两种不同的蛋白质-蛋白质相互作用：R12是Hha所必需的。结合，并不影响H-NS二聚体的形成，和R15不影响Hha的结合，但H-NS，二聚体的正确折叠是必不可少的。我们的研究结果表明，Hha-H-NS相互作用和H-NS二聚化之间的密切结构连接，可能参与了一个可能的机制，为Hha的调节H-NS的活性。(c)2006爱思唯尔有限公司保留所有权利。
Bacterial nucleoid-associated proteins H-NS and Hha modulate gene expression in response to environmental factors. The N-terminal domain of H-NS is involved in homomeric and heteromeric protein-protein interactions. Homomeric interaction leads to the formation of dimers and higher oligomers. Heteromeric interactions with Hha-like proteins modify the modulatory properties of H-NS. In this study, we have used NMR and mutagenesis of the N-terminal domain of H-NS to identify the Hha-binding region around helices H1 and H2 of H-NS. Two conserved arginine residues, R12 and R15, located in the same side and in adjacent turns of helix H2 are shown to be involved in two different protein-protein interactions: R12 is essential for Hha. binding and does not affect H-NS dimer formation, and R15 does not affect Hha binding but is essential for the proper folding of H-NS, dimers.Our results demonstrate a close structural connection between Hha-H-NS interactions and H-NS dimerization that may be involved in a possible mechanism for the modulation of the H-NS regulatory activity by Hha. (c) 2006 Elsevier Ltd. All rights reserved.