Abstract 1978 Harnessing Cellular Metabolite Screening for RNA-Targeting Small Molecule Drug Discovery

DbpA is a DEAD-box RNA helicase involved in the maturation of the peptidyl transferase center in Escherichia coli (E.coli).DbpA is highly conserved in bacteria, and its function is conserved in humans.Previous work has shown that the removal of the dbpA gene does not result in a growth phenotype in E. coli cells during the exponential phase.Our data agrees with previous results.Importantly, our data demonstrate a slow-growth phenotype in cells lacking the DbpA protein during the late stationary phase.This is the first time a phenotype has been observed in cells lacking the DbpA protein.Subsequently, we performed comparative, label-free proteomics analysis using LC-MS/MS on cells either lacking or possessing the DbpA protein during both the exponential and stationary phases.The ribosomal proteins L10, L11, and L29, as well as DEAD-box helicases DeaD and RhlE, are increased in abundance during the exponential growth phase in cells lacking the DbpA protein compared to cells possessing this protein.In cells possessing the DbpA protein, its abundance increases during the stationary phase compared to the exponential phase.Lastly, the abundances of several proteins involved in E.coli's oxidative stress pathway are increased in cells lacking the DbpA protein during both the exponential and stationary phases.Oxidative stress damages ribosomal proteins.The finding that proteins implicated in oxidative stress show increased abundances during the exponential and stationary phases in cells lacking DbpA indicates that DbpA is involved in the repair of the ribosomal large subunit during the exponential phase, in addition to its assembly.Furthermore, our proteomics analysis data reveal that the proteins L10, L11, L29, DeaD, and RhlE substitute for the function of DbpA during ribosome assembly and/or repair in the exponential phase in cells lacking the DbpA protein.On the other hand, during the stationary phase, new ribosomes are not produced, and oxidative stress increases.