分會(huì)

第四十七分會(huì)：質(zhì)譜分析

摘要

太陽(yáng)能作為清潔且可持續(xù)的能源，可以有效降低化石燃料的消耗并減緩全球變暖。同時(shí)自然界的光合作用啟發(fā)人們將光能儲(chǔ)存在化學(xué)能中可以實(shí)現(xiàn)更高效的太陽(yáng)能存儲(chǔ)，但利用半導(dǎo)體材料在光驅(qū)動(dòng)下實(shí)現(xiàn)CO2到有機(jī)物的高效率轉(zhuǎn)換仍面臨挑戰(zhàn)。近年來(lái)，一種新穎的半導(dǎo)體材料-微生物復(fù)合系統(tǒng)的概念被提出，該系統(tǒng)將半導(dǎo)體的高效光捕獲能力和生物酶的高效催化能力結(jié)合來(lái)實(shí)現(xiàn)光能至化學(xué)能轉(zhuǎn)化。其中，Moorella thermoacetica (M. thermoacetica)-CdS復(fù)合系統(tǒng)可以高效利用太陽(yáng)能固定CO2為有機(jī)物乙酸，為實(shí)現(xiàn)人造光合作用開(kāi)辟了新道路。 為了進(jìn)一步研究半導(dǎo)體到微生物的電子轉(zhuǎn)移及復(fù)合人造光合系統(tǒng)固定CO2的過(guò)程從而優(yōu)化系統(tǒng)的光能-化學(xué)能轉(zhuǎn)化效率，我們利用質(zhì)譜分析手段首次采用非標(biāo)定量蛋白質(zhì)組學(xué)、代謝組學(xué)方法對(duì)M. theroacetica-CdS復(fù)合系統(tǒng)的工作運(yùn)行機(jī)制進(jìn)行了深入探討。研究發(fā)現(xiàn)M. thermoacetica表面?zhèn)鬏旊娮拥哪さ鞍自贑dS及光照刺激后表達(dá)量明顯上調(diào)，包括被普遍認(rèn)可的固定CO2的Wood-Ljungdahl通路。據(jù)此，我們提出了光生電子轉(zhuǎn)移至胞內(nèi)及還原CO2的可能途徑。通過(guò)COG功能注釋及STRING蛋白相互作用網(wǎng)絡(luò)分析，我們也發(fā)現(xiàn)M. thermoacetica在光合成之后整體代謝狀態(tài)更為活躍，特別是與能量代謝相關(guān)的糖酵解和三羧酸循環(huán)通路，進(jìn)而我們利用靶向代謝組技術(shù)并結(jié)合蛋白質(zhì)組學(xué)提出了細(xì)胞質(zhì)內(nèi)直接生成ATP及通過(guò)NADH氧化耦合化學(xué)滲透質(zhì)子梯度驅(qū)動(dòng)ATP合成的能量?jī)?chǔ)存新推論。未來(lái)有望在此機(jī)制研究的基礎(chǔ)上，采用生物技術(shù)例如基因工程等手段來(lái)優(yōu)化人造光合成系統(tǒng)。 As a clean and sustainable energy source, solar energy can effectively reduce the consumption of fossil fuels and slow down global warming. However, how to transfer solar energy into chemical energy efficiently remains to be challengeable. Recently, a novel idea which combines highly efficient inorganic light absorbers with highly specific biocatalysts has been proposed for solar-powered biomanufacturing to pave the way in artificial photosynthesis. But this biocatalytic process remains obscure, which is becoming the bottleneck for the development of state-of-the-art bio-abiotic hybrid systems. Therefore, in order to optimize the solar-chemical energy conversion efficiency of the bio-abiotic hybrid system, we studied the mechanism of well-documented Moorella thermoacetica-CdS (cadmium sulfide quantum dots) biohybrid system, involving photo-electrons transportation from CdS to bacterium, CO2 fixation and energy conservation process by label-free quantitative proteomic and metabolomic technologies. Results showed up-regulation of many electron-transfer related membrane-associated enzymes in M. thermoacetica-CdS after photo illumination and the Wood-Ljungdahl pathway (WLP) that has been considered as the main approach for CO2 fixation was found to be highly activated by CdS. Targeted metabolite quantification revealed that energy-metabolism-associated glycolysis and the tricarboxylic acid (TCA) cycle were also activated. Therefore, we propose an energy-conservation scheme to the M. thermoacetica-CdS hybrid system, i.e., glycolysis and the TCA cycle along with the oxidation of acetyl-coenzyme A (CoA) and NADH, in addition to the well-documented chemiosmotic proton gradient-driven ATP production by ATPase. In the future, we expect that the study can be helpful to guide the design of effective and biocompatible photo-biocatalytic systems.

關(guān)鍵詞

微生物光合成;蛋白質(zhì)組學(xué);代謝組學(xué);二氧化碳還原

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何鶯 復(fù)旦大學(xué)、韓國(guó)斌 廣州國(guó)家實(shí)驗(yàn)室 共2人點(diǎn)贊了這篇線上墻報(bào)。