Systems analysis of the CO2 concentrating mechanism in cyanobacteria

eLife

Niall M Mangan¹  Michael P Brenner¹ 

[1] School of Engineering and Applied Sciences and Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, United States;

关键词: cyanobacteria;    carboxysome;    carbon fixation;    systems modeling;   

DOI  :  10.7554/eLife.02043

来源: DOAJ

【 摘 要 】

Cyanobacteria are photosynthetic bacteria with a unique CO2 concentrating mechanism (CCM), enhancing carbon fixation. Understanding the CCM requires a systems level perspective of how molecular components work together to enhance CO2 fixation. We present a mathematical model of the cyanobacterial CCM, giving the parameter regime (expression levels, catalytic rates, permeability of carboxysome shell) for efficient carbon fixation. Efficiency requires saturating the RuBisCO reaction, staying below saturation for carbonic anhydrase, and avoiding wasteful oxygenation reactions. We find selectivity at the carboxysome shell is not necessary; there is an optimal non-specific carboxysome shell permeability. We compare the efficacy of facilitated CO2 uptake, CO2 scavenging, and [Formula: see text] transport with varying external pH. At the optimal carboxysome permeability, contributions from CO2 scavenging at the cell membrane are small. We examine the cumulative benefits of CCM spatial organization strategies: enzyme co-localization and compartmentalization.

【 授权许可】

Unknown