GSE118519
Functional cooperation of glycine synthase-reductase pathway with Wood-Ljungdahl pathway for autotrophic growth of Clostridium drakei
The Wood-Ljungdahl pathway in acetogens converts C1 compounds, such as CO2 and CO, into acetyl-CoA. Similarly, the glycine synthase pathway assimilates C1 compounds into glycine. Partial glycine synthase genes are widely conserved in the Wood-Ljungdahl pathway gene cluster but functional relationship between the pathways in autotrophic condition remains unknown. To comprehend, we assembled Clostridium drakei genome (5.7-Mbp) with intact glycine synthase pathway and constructed a genome-scale metabolic model, iSL836, predicting increased metabolic flux rates of the Wood-Ljungdahl pathway and the glycine synthase-reductase associated reactions under autotrophic conditions. Along with the observation of significant transcriptional activation of genes in the pathways, surprisingly, 13C-labeling experiments and enzyme activity assays confirmed the strain synthesizes glycine and converts into acetyl-phosphate. This study suggests the Wood-Ljungdahl and the glycine synthase-reductase pathways convert CO2 into acetyl-CoA and acetyl-phosphate, respectively. In our knowledge, this is the first report on co-utilization of the pathways under autotrophic growth in acetogen. Overall design: Profile of whole transcripts of Clostridium drakei generated by deep sequencing using Miseq