本文選題：結(jié)核分枝桿菌 + EspB��； 參考：《生物化學(xué)與生物物理進(jìn)展》2017年05期

【摘要】：結(jié)核分枝桿菌作為肺結(jié)核病的病原菌,在人類中致死率遠(yuǎn)高于其他病原菌.結(jié)核分枝桿菌具有特殊的疏水性細(xì)胞壁結(jié)構(gòu),這種致密的細(xì)胞壁結(jié)構(gòu)幫助結(jié)核分枝桿菌抵御外界環(huán)境壓力和來自宿主細(xì)胞的毒素.同時,它利用特殊的分泌系統(tǒng)將體內(nèi)的毒力蛋白輸出體外,ESX-1分泌系統(tǒng)就是其中之一.結(jié)核分枝桿菌ESX-1系統(tǒng)在結(jié)核分枝桿菌進(jìn)入宿主細(xì)胞吞噬小體、逃逸至細(xì)胞質(zhì)以及殺死吞噬細(xì)胞這些過程中發(fā)揮重要作用.研究表明,在結(jié)核分枝桿菌內(nèi)膜上存在一個由多亞基組成、旨在幫助結(jié)核分枝桿菌向外輸送分泌蛋白的分泌裝置.在這個分泌裝置的幫助下,結(jié)核分枝桿菌重要的毒力蛋白ESAT-6跨內(nèi)膜向外分泌,EspB也通過這個內(nèi)膜上的分泌裝置被轉(zhuǎn)運(yùn)至胞外.EspB存在于靜置培養(yǎng)的結(jié)核分枝桿菌的膠囊層中,也可在振蕩培養(yǎng)的結(jié)核分枝桿菌的培養(yǎng)液中被檢測.通過X射線晶體衍射分析,我們解析了EspB的晶體結(jié)構(gòu),相比于其他同源結(jié)構(gòu),發(fā)現(xiàn)了EspB的不同構(gòu)象,即EspB單體能夠自組裝成為七聚體的規(guī)則結(jié)構(gòu),聯(lián)系其與毒力因子ESAT-6具有共分泌的特點,七聚體構(gòu)象的發(fā)現(xiàn)為解釋EspB在結(jié)核分枝桿菌向外分泌蛋白的過程中發(fā)揮的作用提供線索,即EspB具有錨定在結(jié)核分枝桿菌膠囊層中,作為運(yùn)輸ESAT-6的孔道而存在的可能.
[Abstract]:As a pathogen of pulmonary tuberculosis, Mycobacterium tuberculosis has a higher mortality rate in humans than other pathogens. Mycobacterium tuberculosis has a special hydrophobic cell wall structure which helps Mycobacterium tuberculosis withstand environmental pressures and toxins from host cells. At the same time, it uses the special secretion system to export virulence protein in vivo to in vitro ESX-1 secretion system is one of them. Mycobacterium tuberculosis ESX-1 system plays an important role in the process of mycobacterium tuberculosis entering host cell phagocytosome escaping to cytoplasm and killing phagocyte. It has been shown that there is a secretory device composed of multiple subunits on the intima of Mycobacterium tuberculosis, which is designed to help mycobacterium tuberculosis transport secretory protein outward. With the help of this secretory device, ESAT-6, an important virulence protein of Mycobacterium tuberculosis, is also transported to the extracellular layer of Mycobacterium tuberculosis through the transintimal secretory device. EspB exists in the capsule layer of Mycobacterium tuberculosis in static culture. It can also be detected in the medium of oscillating culture of Mycobacterium tuberculosis. The crystal structure of EspB was analyzed by X-ray crystal diffraction. Compared with other homologous structures, we found different conformation of EspB, that is, the regular structure of EspB monomers can self-assemble into heptopolymer. In connection with the co-secretion of EspB with virulence factor ESAT-6, the octamer conformation provides clues for explaining the role of EspB in the process of mycobacterium tuberculosis into exocrine protein, that is, EspB is anchored in the capsule layer of Mycobacterium tuberculosis. The possibility of being a channel for transporting ESAT-6.
【作者單位】： 中國科學(xué)院生物物理研究所生物大分子國家重點實驗室;中國科學(xué)院大學(xué);
【基金】：中國科學(xué)院戰(zhàn)略性先導(dǎo)科技專項(XDB08020202) 國家生物大分子重點實驗室資助項目~~
【分類號】：R378.911
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本文編號：1801488