GENETIC ORGANIZATION AND CHARACTERIZATION OF THE MAU GENE-CLUSTER, WHICH CONCERNED THE INITIAL STEP OF ELECTRON-TRANSPORT CHAINS INVOLVED IN METHYLAMINE, OXIDATION OF THE OBLIGATE METHYLOTROPH METHYLOMONAS SP.STRAIN-J

A gene cluster encoding methylamine dehydrogenase (MADH) and its prima ry electron acceptor, azurin iso-2 (the initial step of Electron trans port chains involved in methylamine oxidation) of the obligate methylo troph Methylomonas sp. strain J (Methylomonas J) was characterized. PC R products synthesized using primers based on the N- and C-terminal am ino acid sequences of MADH light subunit from the facultative methylot roph Methylobacterium extorquens AM1 were used as probes for cloning. Fourteen open reading frames were found in a cloned EcoRI-PstI fragmen t consisting of a total of 11,549 bp. Eight open reading frames were i dentified as mauFBEDAGLM based on the high homology 19 those from Meth ylophilus methylotrophs W3A1-NS. The mauA acid mauB genes encode L sub unit and H subunit of MADH, respectively. The mauO which encodes azuri n iso-2, a primary electron acceptor from MADH of Methylomonas J. was located downstream from the mauFBEDAGLM genes and the direction of tra nscription of this gene was found to be opposite to that of the mau ge ne cluster. Northern blotting analysis suggested that the expression o f the mau gene cluster and the mauO gene is co-regulated. These result s suggest that dynamic gene recruitment occurred for the initial step of the electron transport chains involved in methylamine oxidation of methylotrophs.