Wen Yurong, Ouyang Zhenlin, Yu Yue, Zhou Xiaorong, Pei Yingmei, Devreese Bart, Higgins Paul G, Zheng Fang
Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China.
Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China.
Nucleic Acids Res. 2017 Sep 19;45(16):9773-9787. doi: 10.1093/nar/gkx624.
AdeR-AdeS is a two-component regulatory system, which controls expression of the adeABC efflux pump involved in Acinetobacter baumannii multidrug resistance. AdeR is a response regulator consisting of an N-terminal receiver domain and a C-terminal DNA-binding-domain. AdeR binds to a direct-repeat DNA in the intercistronic region between adeR and adeABC. We demonstrate a markedly high affinity binding between unphosphorylated AdeR and DNA with a dissociation constant of 20 nM. In addition, we provide a 2.75 Å crystal structure of AdeR DNA-binding-domain complexed with the intercistronic DNA. This structure shows that the α3 and β hairpin formed by β5-β6 interacts with the major and minor groove of the DNA, which in turn leads to the introduction of a bend. The AdeR receiver domain structure revealed a dimerization motif mediated by a gearwheel-like structure involving the D108F109-R122 motif through cation π stack interaction. The structure of AdeR receiver domain bound with magnesium indicated a conserved Glu19Asp20-Asp63 magnesium-binding motif, and revealed that the potential phosphorylation site Asp63OD1 forms a hydrogen bond with Lys112. We thus dissected the mechanism of how AdeR recognizes the intercistronic DNA, which leads to a diverse mode of response regulation. Unlocking the AdeRS mechanism provides ways to circumvent A. baumannii antibiotic resistance.
AdeR - AdeS是一种双组分调节系统，它控制着鲍曼不动杆菌多药耐药性中涉及的adeABC外排泵的表达。AdeR是一种应答调节因子，由一个N端接收结构域和一个C端DNA结合结构域组成。AdeR与adeR和adeABC之间的基因间区域中的直接重复DNA结合。我们证明了未磷酸化的AdeR与DNA之间具有显著的高亲和力结合，解离常数为20 nM。此外，我们提供了与基因间DNA复合的AdeR DNA结合结构域的2.75 Å晶体结构。该结构表明，由β5 - β6形成的α3和β发夹与DNA的大沟和小沟相互作用，进而导致弯曲的产生。AdeR接收结构域结构揭示了一种由涉及D108F109 - R122基序的齿轮状结构通过阳离子π堆积相互作用介导的二聚化基序。与镁结合的AdeR接收结构域的结构显示了一个保守的Glu19Asp20 - Asp63镁结合基序，并揭示了潜在的磷酸化位点Asp63OD1与Lys112形成氢键。因此，我们剖析了AdeR识别基因间DNA的机制，这导致了多种应答调节模式。解开AdeRS机制为规避鲍曼不动杆菌抗生素耐药性提供了途径。
