15th International Conference on Metabolomics & Systems Biology
University of Turku, Finland
Title: Evaluation of metabolic redox homeostasis in prokaryotes
Biography: Sanna Kreula
The work focuses on cellular redox homeostasis in prokaryotic micro-organisms, and specifically on factors associated with nicotinamide adenine cofactor [NADP(H) and NAD(H)] metabolism in E. coli and photoautotrophic cyanobacterium Synechocystis sp. PCC 6803. These cofactors participate in numerous electron transfer reactions in the cell, linking enzymatic reactions with the overall energy metabolism with biosynthetic reactions and housekeeping functions. Obtaining a comprehensive view of the interactions and the regulatory circuits is thus of central importance in understanding the adaptation to different environmental conditions, such as those involved with the transition between autotrophic and heterotrophic growth modes in cyanobacteria. The principal objective is to study the role of the proton gradient-coupled pyridine nucleotide transhydrogenase PntAB. Functional characterization combined with structral modelling of PntAB in Synechocystis sp. PCC 6803 has been carried out, and information-rich networks have been created to identify identify novel candidates involved in the NADP(H)-regulation in different organisms. In addition, PntAB is studied through deletion and over-expression mutants under anaerobic fermentative conditions and under different pH’s in E. coli. Specifically, the initiative is to elucidate to what extent the regulation of the cofactor redox balance takes place at the level of alternative catabolic routes in glucose breakdown, and what is the role of PntAB under these specific conditions. The approach is to generate pntAB over-expression and knock-out strains, and to compare them in phenotypic growth properties as well as in respect to changes in the central carbon metabolism by analyzing the distribution of local ratios of amino acids using C13 labelled glucose as a probe.