Studies on the Regulation of (p)ppGpp Metabolism and Its Perturbation Through the Over-Expression of Nudix Hydrolases in .

Stringent response mediated by modified guanosine nucleotides is conserved across bacteria and is regulated through the Rel/Spo functions. In , RelA and SpoT proteins synthesize the modified nucleotides ppGpp and pppGpp, together referred to as (p)ppGpp. SpoT is also the primary (p)ppGpp hydrolase.

Activation of RelA by pppGpp as the basis for its differential toxicity over ppGpp in .

The nucleotide derivatives (p)ppGpp, comprising ppGpp and pppGpp, are important signalling molecules that control various facets of gene regulation and protein synthesis in Escherichia coli. Their synthesis is catalysed by RelA (in response to amino acid limitation) and by SpoT (in response to the limitation of carbon source or fatty acids). SpoT is also a hydrolase for degradation of both ppGpp and pppGpp, while GppA catalyses the conversion of pppGpp to ppGpp.

A Novel Gene Contributing to the Initiation of Fatty Acid Biosynthesis in Escherichia coli.

Type II fatty acid biosynthesis in bacteria can be broadly classified into the initiation and elongation phases. The biochemical functions defining each step in the two phases have been studied Among the β-ketoacyl-acyl carrier protein (ACP) synthases, FabH catalyzes the initiation reaction, while FabB and FabF, which primarily catalyze the elongation reaction, can also drive initiation as side reactions. A role for FabB and FabF in the initiation of fatty acid biosynthesis would be supported by the viability of the mutant.