Structural Analysis of a Virulence Gene Regulator in Chlamydia

描述(申请人提供)：衣原体感染对公共健康有巨大的影响，导致不孕、失明、肺炎，并与动脉粥样硬化病变和心脏病的形成有关。这些专性细胞内细菌在与发病密切相关的发育周期中永久存在。我们对控制衣原体发育周期和发病机制的因素和机制的了解存在严重不足；然而，转录调控在衣原体发育中起着支配作用。阐明转录调控因子和机制对于了解衣原体的发育和发病机制，定义毒力决定因素，并为未来的疾病干预策略确定新的靶点至关重要。我们研究的长期目标是确定调控衣原体发育和发病的分子机制。这一建议是为了获得衣原体转录因子ChxR的结构信息，ChxR对衣原体的发育和发病具有重要作用。ChxR是一种26kD的蛋白，与研究广泛的两组分信号转导反应调节因子OmpR亚家族同源。我们的中心假设是，天然的ChxR保持在与磷酸化的OmpR反应调节器的瞬时激活状态相对应的结构构象中。为了产生关键的初步数据以最终检验所述的假设，我们提出了两个具体的目标：1)确定完整的全长ChxR反应调节子的三维晶体结构；2)确定ChxR受体-效应域的界面。作为拟议研究的结果，将确定转录调控所需的区域和残基，从而使未来的功能研究能够阐明ChxR的确切调控机制。 公共卫生相关性：拟议的研究将有助于我们了解如何以及什么控制医学上重要的细菌衣原体的发育和疾病。此外，这项研究中的反应调节因子在细菌中广泛存在，而在哺乳动物中不存在，因此是开发新抗菌剂的有吸引力的目标。

DESCRIPTION (provided by applicant): Chlamydiae infections have an immense impact of public health causing sterility, blindness, pneumonia, and correlated with formation of atherosclerotic lesions and heart disease. These obligate intracellular bacteria are perpetuated through a developmental cycle that is intimately linked to pathogenesis. There is a critical deficiency in our understanding of the factors and mechanisms that control the development cycle and pathogenesis; however, transcriptional regulation has a governing role in chlamydial development. Elucidating transcriptional regulatory factors and mechanisms employed is central to understanding chlamydial development and pathogenesis, defining virulence determinants, and identifying novel targets for future disease intervention strategies. The long-term goal of our research is to characterize the molecular mechanisms that regulate chlamydial development and pathogenesis. This proposal is designed to gain structural information of a chlamydial transcription factor, ChxR, which is important for chlamydial development and pathogenesis. ChxR is a 26 kD protein homologous to the well-studied and widespread OmpR subfamily of two-component signal transduction response regulators. Our central hypothesis is that native ChxR is maintained in a structural conformation that corresponds to the transient active state of the phosphorylated OmpR response regulators. To generate critical preliminary data for eventual testing the stated hypothesis, we propose two Specific Aims; 1) Determine the three-dimensional crystal structure of intact full-length ChxR response regulator and 2) Determine ChxR receiver-effector domain interface. As a result of the proposed studies, regions and residues requisite for transcriptional regulation will be identified allowing future functional studies to elucidate the precise regulatory mechanism of ChxR. PUBLIC HEALTH RELEVANCE: Proposed studies will facilitate our understanding of how and what controls development and disease for the medically important bacteria, Chlamydia. Furthermore, response regulators such as the one in this study are widespread in bacteria and absent in mammals and as such, are attractive targets for development of new antimicrobials.