The pyrroloquinoline quinone synthesis genes of Gluconobacter oxydans

A Tn5-induced glucose dehydrogenase (GDH) deficient mutant of Gluconobacter oxydans IFO 3293 was characterised. DNA sequencing showed that the inserti on site occurred in an open reading frame with homology to the pqqE gene. I t was shown that acid production could be restored by addition of the coenz yme pyrroloquinoline quinone (PQQ) to the medium. The pqq cluster of G. oxy dans ATCC 9937 was cloned and sequenced. It has five genes pqqA-E. The clus ter could complement the Tn5-induced mutation in IFO 3293. Pulsed-field gel electrophoresis suggested that the pqq genes are not closely linked to the ribF gene that produces the riboflavin cofactor for the gluconic acid dehy drogenase. (C) 2000 Federation of European Microbiological Societies. Publi shed bq Elsevier Science B.V. All rights reserved.