Dynamic Local Polymorphisms in the Gbx1 Homeodomain Induced by DNA Binding.
Dynamic Local Polymorphisms in the Gbx1 Homeodomain Induced by DNA Binding.
复制标题
DNA 结合诱导的 Gbx1 同源域动态局部多态性。
DOI：
10.1016/j.str.2016.05.013
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Serrano,Pedro
中科院分区：
文献类型：
--
作者：
Proudfoot,Andrew;Geralt,Michael;Elsliger,Marc-Andre;Wilson,IanA;Wüthrich,Kurt;Serrano,Pedro
原肠形成脑同源盒1（Gbx1）基因编码Gbx1同源结构域，其靶向双链DNA （dsDNA）中的TAATTA基序。Gbx1中的Glu17和Arg52残基形成盐桥，在同源同源结构域dna复合物的晶体结构和分子动力学模拟中得以保存。相比之下，我们的核磁共振（NMR）研究表明，DNA与Gbx1的结合诱导了动态的局部多态性，其中包括Glu17-Arg52盐桥的断裂。为了研究这种相互作用，我们产生了一个具有Glu17Arg和Arg52Glu突变的变体，其表现出与野生型蛋白相同的折叠，但对dsDNA的亲和力降低了2倍。对自由形式的Gbx1同源结构域、Gbx1[E17R，R52E]变体和Gbx1同源结构域-DNA复合物的核磁共振结构分析表明，DNA结合的Gbx1中Glu17-Arg52盐桥的短暂断裂促进了Arg52侧链与DNA主链的稳定相互作用。
TheGastrulation Brain Homeobox 1(Gbx1) gene encodes the Gbx1 homeodomain that targets TAATTA motifs in double-stranded DNA (dsDNA). Residues Glu17 and Arg52 in Gbx1 form a salt bridge, which is preserved in crystal structures and molecular dynamics simulations of homologous homeodomain-DNA complexes. In contrast, our nuclear magnetic resonance (NMR) studies show that DNA binding to Gbx1 induces dynamic local polymorphisms, which include breaking of the Glu17-Arg52 salt bridge. To study this interaction, we produced a variant with Glu17Arg and Arg52Glu mutations, which exhibited the same fold as the wild-type protein, but a 2-fold reduction in affinity for dsDNA. Analysis of the NMR structures of the Gbx1 homeodomain in the free form, the Gbx1[E17R,R52E] variant, and a Gbx1 homeodomain-DNA complex showed that stabilizing interactions of the Arg52 side chain with the DNA backbone are facilitated by transient breakage of the Glu17-Arg52 salt bridge in the DNA-bound Gbx1.