分会

第四十七分会：质谱分析

摘要

太阳能作为清洁且可持续的能源，可以有效降低化石燃料的消耗并减缓全球变暖。同时自然界的光合作用启发人们将光能储存在化学能中可以实现更高效的太阳能存储，但利用半导体材料在光驱动下实现CO2到有机物的高效率转换仍面临挑战。近年来，一种新颖的半导体材料-微生物复合系统的概念被提出，该系统将半导体的高效光捕获能力和生物酶的高效催化能力结合来实现光能至化学能转化。其中，Moorella thermoacetica (M. thermoacetica)-CdS复合系统可以高效利用太阳能固定CO2为有机物乙酸，为实现人造光合作用开辟了新道路。 为了进一步研究半导体到微生物的电子转移及复合人造光合系统固定CO2的过程从而优化系统的光能-化学能转化效率，我们利用质谱分析手段首次采用非标定量蛋白质组学、代谢组学方法对M. theroacetica-CdS复合系统的工作运行机制进行了深入探讨。研究发现M. thermoacetica表面传输电子的膜蛋白在CdS及光照刺激后表达量明显上调，包括被普遍认可的固定CO2的Wood-Ljungdahl通路。据此，我们提出了光生电子转移至胞内及还原CO2的可能途径。通过COG功能注释及STRING蛋白相互作用网络分析，我们也发现M. thermoacetica在光合成之后整体代谢状态更为活跃，特别是与能量代谢相关的糖酵解和三羧酸循环通路，进而我们利用靶向代谢组技术并结合蛋白质组学提出了细胞质内直接生成ATP及通过NADH氧化耦合化学渗透质子梯度驱动ATP合成的能量储存新推论。未来有望在此机制研究的基础上，采用生物技术例如基因工程等手段来优化人造光合成系统。 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.

关键词

微生物光合成;蛋白质组学;代谢组学;二氧化碳还原

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何莺 复旦大学、韩国斌 中国科学院杭州医学研究所 共2人点赞了这篇线上墙报。