Celebration of Learning

Confirmation of the function of Mrub1080 as γ-glutamyl kinase (ProB) in Meiothermus ruber

This project is part of the Meiothermus ruber genome analysis project, which uses wet lab procedures and computational analysis to gather evidence of orthologous genes between Escherichia coli and Meiothermus ruber. In previous work, bioinformatics evidence supported the hypothesis that the gene Mrub1080 was an ortholog of E. coli proB. We investigated the biological function of Meiothermus ruber genes proB and proBA using the complementation assay. However, functional analysis proved inconclusive. For this particular research project, we confirmed that weakly complementing E. coli proB- null strains actually contained the desired M. ruber proB and proBA genes (inserted into a pKt1 expression vector), as opposed to being growth artifacts or bacterial contamination. The proB gene encodes the γ-glutamyl kinase (EC 2.7.2.11), which is the first step of the proline biosynthesis pathway (KEGG map number 00330). The proBA gene encodes the first two enzymes of the proline biosynthesis pathway γ-glutamyl kinase (EC 2.7.2.11) and γ-glutamyl phosphate reductase (EC 1.2.1.41), suggesting they are part of an operon.