State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Synth Biol. 2021 Apr 16;10(4):707-715. doi: 10.1021/acssynbio.0c00436. Epub 2021 Mar 16.
Carboxysomes (CBs) are protein organelles in cyanobacteria, and they play a central role in assimilation of CO. Heterologous synthesis of CBs in provides an opportunity for CO-organic compound conversion under controlled conditions but remains challenging; specifically, the CO assimilation efficiency is insufficient. In this study, an auxiliary module was designed to assist self-assembly of CBs derived from a model species cyanobacteria () MED4 for synthesizing in . The results indicated that the structural integrity of synthetic CBs is improved through the transmission electron microscope images and that the CBs have highly efficient CO-concentrating ability as revealed by enzyme kinetic analysis. Furthermore, the bacterial growth curve and C-metabolic flux analysis not only consolidated the fact of CO assimilation by synthetic CBs in but also proved that the engineered strain could efficiently convert external CO to some metabolic intermediates (acetyl-CoA, malate, fumarate, tyrosine, etc.) of the central metabolic pathway. The synthesis of CBs of MED4 in provides prospects for understanding their CO assimilation mechanism and realizing their modular application in synthetic biology.
羧基体（CBs）是蓝细菌中的蛋白细胞器，在 CO 的同化中起着核心作用。在 中异源合成 CBs 为在受控条件下进行 CO-有机化合物转化提供了机会，但仍然具有挑战性；具体来说，CO 同化效率不足。在这项研究中，设计了一个辅助模块，以协助源自模式物种蓝细菌 （）MED4 的 CBs 的自组装，用于在 中合成。结果表明，通过透射电子显微镜图像显示，合成 CBs 的结构完整性得到了提高，并且通过酶动力学分析表明，CBs 具有高效的 CO 浓缩能力。此外，细菌生长曲线和 C 代谢通量分析不仅证实了合成 CBs 在 中进行 CO 同化的事实，还证明了工程菌株能够有效地将外部 CO 转化为中心代谢途径的一些代谢中间产物（乙酰辅酶 A、苹果酸、富马酸、酪氨酸等）。在 中合成 MED4 的 CBs 为理解其 CO 同化机制和实现其在合成生物学中的模块化应用提供了前景。
