A novel allele of kaiA shortens the circadian period and strengthens interaction of oscillator components in the cyanobacterium Synechococcus elongatus PCC 7942.

The basic circadian oscillator of the unicellular fresh water cyanobacterium Synechococcus elongatus PCC 7942, the model organism for cyanobacterial circadian clocks, consists of only three protein components: KaiA, KaiB, and KaiC. These proteins, all of which are homomultimers, periodically interact to form large protein complexes with stoichiometries that depend on the phosphorylation state of KaiC. KaiA stimulates KaiC autophosphorylation through direct physical interactions.

The complete sequence and functional analysis of pANL, the large plasmid of the unicellular freshwater cyanobacterium Synechococcus elongatus PCC 7942.

Two endogenous plasmids are present in Synechococcus elongatus PCC 7942, a model organism for studying photosynthesis and circadian rhythms in cyanobacteria. The large plasmid, pANL, was shown previously to be involved in adaptation of S. elongatus cells to sulfur starvation, which provided the first evidence of cellular function of a cyanobacterial plasmid.

High-throughput functional analysis of the Synechococcus elongatus PCC 7942 genome.

Synechococcus elongatus PCC 7942 was the first cyanobacterial strain to be reliably transformed by exogenously added DNA and has become the model organism for cyanobacterial circadian rhythms. With a small genome (2.7 Mb) and well-developed genetic tools, PCC 7942 provides an exceptional opportunity to elucidate the circadian mechanism through genetics.

IIA(Glc) allosteric control of Escherichia coli glycerol kinase: binding site cooperative transitions and cation-promoted association by Zinc(II).

The catalytic activity of glycerol kinase (EC 2.7.1.

Reverse genetics of Escherichia coli glycerol kinase allosteric regulation and glucose control of glycerol utilization in vivo.

Reverse genetics is used to evaluate the roles in vivo of allosteric regulation of Escherichia coli glycerol kinase by the glucose-specific phosphocarrier of the phosphoenolpyruvate:glycose phosphotransferase system, IIA(Glc) (formerly known as III(glc)), and by fructose 1,6-bisphosphate. Roles have been postulated for these allosteric effectors in glucose control of both glycerol utilization and expression of the glpK gene. Genetics methods based on homologous recombination are used to place glpK alleles with known specific mutations into the chromosomal context of the glpK gene in three different genetic backgrounds.