Pioneering precision in markerless strain development for Synechococcus sp. PCC 7002.

Marine cyanobacteria such as Picosynechococcus sp. (formerly called Synechococcus sp.) PCC 7002 are promising chassis for photosynthetic production of commodity chemicals with low environmental burdens.

L-Lactate treatment by photosynthetic cyanobacteria expressing heterogeneous L-lactate dehydrogenase.

L-Lactate is a major waste compound in cultured animal cells. To develop a sustainable animal cell culture system, we aimed to study the consumption of L-lactate using a photosynthetic microorganism. As genes involved in L-lactate utilization were not found in most cyanobacteria and microalgae, we introduced the NAD-independent L-lactate dehydrogenase gene from Escherichia coli (lldD) into Synechococcus sp.

Nitrogen Availability Affects the Metabolic Profile in Cyanobacteria.

Nitrogen is essential for the biosynthesis of various molecules in cells, such as amino acids and nucleotides, as well as several types of lipids and sugars. Cyanobacteria can assimilate several forms of nitrogen, including nitrate, ammonium, and urea, and the physiological and genetic responses to these nitrogen sources have been studied previously. However, the metabolic changes in cyanobacteria caused by different nitrogen sources have not yet been characterized.

The phototroph-specific β-hairpin structure of the γ subunit of FF-ATP synthase is important for efficient ATP synthesis of cyanobacteria.

The FF synthase produces ATP from ADP and inorganic phosphate. The γ subunit of FF ATP synthase in photosynthetic organisms, which is the rotor subunit of this enzyme, contains a characteristic β-hairpin structure. This structure is formed from an insertion sequence that has been conserved only in phototrophs.

The β-hairpin region of the cyanobacterial F-ATPase γ-subunit plays a regulatory role in the enzyme activity.

The γ-subunit of cyanobacterial and chloroplast ATP synthase, the rotary shaft of F-ATPase, equips a specific insertion region that is only observed in photosynthetic organisms. This region plays a physiologically pivotal role in enzyme regulation, such as in ADP inhibition and redox response. Recently solved crystal structures of the γ-subunit of F-ATPase from photosynthetic organisms revealed that the insertion region forms a β-hairpin structure, which is positioned along the central stalk.

The N-terminal region of the ϵ subunit from cyanobacterial ATP synthase alone can inhibit ATPase activity.

ATP hydrolysis activity catalyzed by chloroplast and proteobacterial ATP synthase is inhibited by their ϵ subunits. To clarify the function of the ϵ subunit from phototrophs, here we analyzed the ϵ subunit-mediated inhibition (ϵ-inhibition) of cyanobacterial F-ATPase, a subcomplex of ATP synthase obtained from the thermophilic cyanobacterium BP-1. We generated three C-terminal α-helix null ϵ-mutants; one lacked the C-terminal α-helices, and in the other two, the C-terminal conformation could be locked by a disulfide bond formed between two α-helices or an α-helix and a β-sandwich structure.