Fig. 1: Engineering and characterization of empty α-carboxysome shells.
From: Reprogramming bacterial protein organelles as a nanoreactor for hydrogen production
a Schematic of the carboxysome structure and metabolic pathways. The carboxysome shell serves as a physical barrier to permit passage of cytosolic bicarbonate (HCO3−) and ribulose-1,5-bisphosphate (RuBP) into the carboxysome. The metabolic product 3-phosphoglycerate (3-PGA) is transported across the shell and is metabolized via the Calvin–Benson–Bassham cycle. b Genetic organizations of the native cso operon, synthetic cso-1 and cso-2 operons. c Thin-section electron microscopy (EM) of E. coli cells expressing the cso-1 operon (left) and cso-2 operon (right), respectively. Arrows indicate α-carboxysome shell particles discerned in the cell. d SDS-PAGE of purified cso-1 (left) and cso-2 (right) shell structures. e Transmission EM of purified cso-1 (top) and cso-2 (middle) shells in the 20% sucrose fractions. Shells with CA are significantly smaller in diameter than those without CA. ***p < 0.001 (p = 0.0007, n = 150, two-tailed unpaired t-test), implying the role of CA in confining shell architecture (bottom). Box and whisker plots indicate the median (middle line in the box), 25th percentile (bottom line of the box), 75th percentile (top line of the box), as well as the minima and maxima (whiskers). Source data underlying c–e are provided as a Source data file.
