Part:BBa_K1790002

HAD

YniC is a sugar phosphatase belonging to the superfamily of haloacid dehalogenase (HAD)-like hydrolases. Its preferred substrate is 2-deoxyglucose-6-phosphate. The phosphatase activity of YniC was first discovered in a high-throughput screen of purified proteins. Phosphatase activity of YniC is dependent on the presence of a divalent cation such as Mg2+, which appears to affect substrate binding. Mutagenesis of the predicted catalytic Asp residues in YniC results in loss of phosphatase activity. A yniC deletion mutant is more sensitive to the presence of 2-deoxyglucose in the growth medium than wild type, while a strain overexpressing yniC tolerates higher concentrations of 2-deoxyglucose. 2-deoxyglucose is taken up by E. coli and is phosphorylated to 2-deoxyglucose-6P, a toxic analog of glucose-6P.

GlnH

The GlnHPQ high-affinity glutamine transport system is a member of the ATP-Binding Cassette (ABC) Superfamily of transporters. Based on sequence similarity, GlnH is the periplasmic glutamine-binding protein, GlnQ is the ATP-binding component, and GlnP is the membrane component of the ABC transporter. Mutation of glnP results in the impaired ability to transport glutamine as well as the inability to utilized glutamine as a sole source of carbon. Expression of the cloned glnHPQ genes on a plasmid vector restored the glnH, glnP and glnQ mutants' abilities to transport glutamine and utilize glutamine as a sole carbon source.