Structure and function of Heparin Binding Hemagglutinin from Mycobacterium tuberculosis

结核病（TB）是全世界死亡的主要原因，其归因于单一细菌结核分枝杆菌（MTB）。TB发病机理的关键方面包括MTB经由MTB与上皮细胞的相互作用从原发感染部位（主要是肺）传播到潜在的任何器官的能力（Russel等人，2010 Science，328：852-856）。该过程需要称为肝素结合血凝素粘附素的关键毒力因子（HBHA，Pethe等人，2001 Nature 412，190-194），一种定位于MTB表面的蛋白质。除了在TB中的相关功能之外，HBHA被认为是TB的诊断和治疗的关键靶标，鉴于MTB的日益增长的多药耐药性，这尤其重要。这项研究的挑战性与HBHA的复杂性有关，HBHA的复杂性阻碍了迄今为止成功采用能够分析蛋白质结构的方法。这种缺乏了解反过来又阻碍了HBHA促进肺外结核传播的机制的表征。该提案旨在解决HBHA的结构和功能机制的雄心勃勃的目标，该蛋白质通过该功能机制促进肺外结核传播机制中的上皮细胞粘附。这是结核病研究的一个里程碑，需要克服重大的实验挑战。我们的研究建议来得正是时候，因为我们现在拥有实现这一主要目标的所有工具、材料和背景研究。我们将联合收割机结合我们在生物分子核磁共振（NMR）光谱学和微生物学的研究计划，以产生一个多学科的调查，以揭示结构，动力学和拓扑结构的HBHA在MTB膜的表面，以及粘附到上皮细胞的机制的细节。我们的跨学科研究的影响将在更广泛的学术界研究结核病感染的潜在分子机制和更广泛的学科，如蛋白质科学，生物化学，核磁共振光谱学，微生物学，细胞和分子生物物理学。预计这项研究的结果可能直接转化为知识，导致新的结核病治疗和诊断方法。

Tuberculosis (TB) is a leading cause of death worldwide due to a single bacterium, Mycobacterium tuberculosis (MTB). Key aspects of TB pathogenesis include the ability of MTB to disseminate from the site of primary infection (primarily the lungs) to potentially any organ (Russel et al, 2010 Science, 328:852-856) via the interaction of MTB with epithelial cells. This process requires a crucial virulence factor called heparin-binding haemagglutinin adhesin (HBHA, Pethe et al., 2001 Nature 412, 190-194), a protein that is localised at the surface of MTB. In addition to the relevant function in TB, HBHA is considered a crucial target for diagnostic and treatment of TB, which is particularly crucial in view of the growing multi-drug resistance of MTB.Currently the structure of HBHA is unknown. The challenging nature of this study is associated with the complex nature of HBHA that has prevented so far the successful employment of methods able to characterise protein structures. This lack of understanding has in turn hampered the characterisation of the mechanisms by which HBHA promotes the extrapulmonary dissemination of TB. The proposal aims at the ambitious target of resolving the structure of HBHA and the functional mechanism by which this protein promotes the adhesion to epithelial cells within the mechanisms of extrapulmunary dissemination of TB. This is a milestone in TB research that requires overcoming significant experimental challenges. Our research proposal comes at a most opportune time since we now have all the tools, materials and background research to achieve this major goal. We will combine our research programmes in biomolecular nuclear magnetic resonance (NMR) spectroscopy and microbiology to generate a multidisciplinary investigation to reveal the structure, dynamics and topology of HBHA at the surface of MTB membranes as well as the details of the mechanism of adhesion to epithelial cells. The impact of our interdisciplinary study will be significant on the wider academic community studying the underlying molecular mechanisms of TB infection and wider disciplines such as protein science, biochemistry, NMR spectroscopy, microbiology, cellular and molecular biophysics. It is anticipated that the outcomes of this research may directly translate into knowledge leading to new therapeutic and diagnostic approaches for TB.