Characterization of the Na+-NQR from V. cholerae

The Na+-pumping NADH-ubiquinone oxidoreductase (Na+-NQR) is anticipated to be a promising target of antibiotics because it is an exclusively prokaryotic enzyme and plays an essential role in bioenergetics in many pathogenic bacteria. To identify the site labeled by a ubiquinone probe, the NqrA subunit was partially digested with V8-protease. The partial digests were subjected to "in-gel" tryptic digestion, followed by MALDI-TOF MS analysis.