Schumacher Maria A, Piro Kevin M, Xu Weijun, Hansen Sonja, Lewis Kim, Brennan Richard G
Department of Biochemistry and Molecular Biology, University of Texas, M. D. Anderson Cancer Center, Unit 1000, Houston, TX 77030, USA.
Science. 2009 Jan 16;323(5912):396-401. doi: 10.1126/science.1163806.
Bacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here, we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic serine/threonine kinase-like fold and can phosphorylate the translation factor EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, approximately 70 degrees DNA bending, and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB.
细菌的多重耐药性在很大程度上导致了抗生素无法根除感染,这是由一小部分称为持留菌的休眠细菌引起的。HipA是大肠杆菌中一种关键的持留因子,通常被转录抑制因子HipB中和,HipB也调节hipBA的表达。在此,我们报告了HipA以及HipA-HipB-DNA复合物的多个结构。HipA具有真核丝氨酸/苏氨酸激酶样折叠结构,能够磷酸化翻译因子EF-Tu,提示了一种通过细胞停滞的持留机制。HipA-HipB-DNA结构揭示了HipB与操纵子的结合机制、约70度的DNA弯曲以及意外的HipA-DNA相互作用。二聚体HipB与两个HipA分子相互作用,通过隔离和构象失活来抑制其激酶活性。综合这些研究,揭示了HipA介导的持留及其被HipB中和的机制。