Spatially Ordered Dynamics of the Bacterial Carbon Fixation Machinery

Abstract

Cyanobacterial carbon fixation is a major component of the global carbon cycle. This process requires the carboxysome, an organelle-like proteinaceous microcompartment that sequesters the enzymes of carbon fixation from the cytoplasm. Here, fluorescently tagged carboxysomes were found to be spatially ordered in a linear fashion. As a consequence, cells undergoing division evenly segregated carboxysomes in a nonrandom process. Mutation of the cytoskeletal protein ParA specifically disrupted carboxysome order, promoted random carboxysome segregation during cell division, and impaired carbon fixation after disparate partitioning. Thus, cyanobacteria use the cytoskeleton to control the spatial arrangement of carboxysomes and to optimize the metabolic process of carbon fixation.

Metabolic and Transcriptomic Phenotyping of Inorganic Carbon Acclimation in the Cyanobacterium Synechococcus elongatus PCC 7942

“…However, ccmK, ccmM, and rbcL showed transient increases in mRNA levels when cells of Synechococcus 7942 were analyzed during the first 60 min after a shift to CO 2 -free air (Woodger et al, 2003). In long-term (24 h) LC-acclimated cells, most of the genes for C i transport return to the control level, whereas the genes for the carboxysome showed decreased transcript levels despite the increased CCM activity and the increased number of this prokaryotic organelle in LC cells (McKay et al, 1993;Savage et al, 2010). The decreased expression of carboxysome shell proteins reflects the lowered growth rate of the cells in LC conditions, which involves decreasing the rate of new synthesis of the carboxysomal proteins.…”

ParP prevents dissociation of CheA from chemotactic signaling arrays and tethers them to a polar anchor

“…17 and 18). ParA-like proteins modulate the localization of cytosolic chemotaxis clusters and carboxysomes in Rhodobacter sphaeroides (19) and Synechococcus elongatus (20), respectively. The localization and activity of ParA-like proteins typically is controlled by ATP binding and hydrolysis, because ATP binding governs their capacity to oligomerize and to interact with other proteins (reviewed in refs.…”

Cell biology: The new cell anatomy

“…Pamela Silver, a synthetic biologist at Harvard Medical School in Boston, Massachusetts, and her colleagues reported 12 last year that in cyanobacteria, certain microcompartments called carboxysomes "more or less stayed in a line down the centre of the cell", says Silver. This tidy arrangement allows cells to allot carboxysomes evenly to daughter cells when dividing.…”