TY - CONF ID - 10442/8344 A1 - Theodorou, M. C. A1 - A1 - Theodorou, E. C. A1 - A1 - Panagiotidis, C. A. A1 - A1 - Kyriakidis, D. A. Y1 - 2006/// T1 - Signal transduction through the AtoS-AtoC/az two component system towards poly (3-OH-butyrate) biosynthesis in E. coli T2 - The FEBS Journal 273:Suppl. 1(Jun2006):99-99 , Τhe 31th FEBS Congress, Istanbul, Turkey, 24 - 26 June, 2006 SN - 1742-464X U3 - 10.1111/j.1742-4658.2006.05277.x PB - Wiley-Blackwell Publishing Ltd. UR - https://hdl.handle.net/10442/8344 N2 - The AtoS-AtoC/Az two-component system activates the ato- DAEB operon expression upon acetoacetate induction for E. coli growth in short-chain fatty acids. It also enhances the poly (3- OH-butyrate) (cPHB) biosynthesis, upon acetoacetate induction as well as in the presence of spermidine. The response regulator of the system is the antizyme (Az) of ornithine decarboxylase and is the product of atoC gene. It belongs to the NtrC-NifA family of sigma54-RNA polymerase transcriptional activators. AtoC contains two putative phosphorylation sites, i.e. a conserved aspartic acid among the response regulators and a histidine residue in an H box consensus sequence, normally common to histidine kinases. We report here, that only phosphorylationcompetent AtoC can lead to enhanced production of cPHB in E. coli, when overexpressed with AtoS. Specifically, upon acetoacetate induction, the mutation of Asp reduces cPHB accumulation, compared with cells expressing wild-type AtoC. The mutation of His residue has an even more pronounced effect. The relative effects of these mutations on cPHB accumulation are consistent with their effects on atoDAEB operon expression, i.e. the mutation of Asp has a more potent phenotype than the substitution of His, in the presence of spermidine. Introduction of both AtoC mutations render the system unresponsive to acetoacetate as well as polyamine, resulting in total abrogation of the AtoS-AtoC/Az overexpression effect phenotype to cPHB levels in E. coli. ER -