Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA.
Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA.
Sci Adv. 2020 May 6;6(19):eaba1269. doi: 10.1126/sciadv.aba1269. eCollection 2020 May.
Carboxysomes, prototypical bacterial microcompartments (BMCs) found in cyanobacteria, are large (~1 GDa) and essential protein complexes that enhance CO fixation. While carboxysome biogenesis has been elucidated, the activity dynamics, lifetime, and degradation of these structures have not been investigated, owing to the inability of tracking individual BMCs over time in vivo. We have developed a fluorescence-imaging platform to simultaneously measure carboxysome number, position, and activity over time in a growing cyanobacterial population, allowing individual carboxysomes to be clustered on the basis of activity and spatial dynamics. We have demonstrated both BMC degradation, characterized by abrupt activity loss followed by polar recruitment of the deactivated complex, and a subclass of ultraproductive carboxysomes. Together, our results reveal the BMC life cycle after biogenesis and describe the first method for measuring activity of single BMCs in vivo.
羧基体，蓝细菌中典型的细菌微室（BMCs），是大型（~1GDa）且必不可少的蛋白质复合物，可增强 CO2 固定。虽然已经阐明了羧基体的生物发生过程，但由于无法在体内随时间追踪单个 BMC，因此这些结构的活性动力学、寿命和降解仍未得到研究。我们开发了一种荧光成像平台，可在不断生长的蓝细菌群体中实时测量羧基体的数量、位置和活性，从而可根据活性和空间动力学将单个羧基体聚类。我们不仅证明了 BMC 的降解，其特征是活性突然丧失，随后失活的复合物向极地招募，还证明了存在超活跃羧基体这一类。总之，我们的结果揭示了生物发生后的 BMC 生命周期，并描述了体内测量单个 BMC 活性的第一种方法。
