AM1 produces pyrroloquinoline quinone (PQQ), the prosthetic group of methanol dehydrogenase. Two gene clusters have been shown to be required for PQQ biosynthesis in this micro-organism and complementation analysis has identified seven genes, and The DNA sequence of was reported previously. This paper reports the sequence of the genomic region corresponding to For consistency, the nomenclature of genes in Klebsiella pneumoniae will be followed. The new nomenclature for genes of AM1 is and In the genomic region sequenced in this study, two open reading frames were found. One of these encodes PqqE, which showed high identity to analogous genes in other bacteria. PqqE also showed identity to MoaA and NifB in the N-terminal region, where a conserved CxxxCxYC sequence was identified. The sequence of the second open reading frame covered both the and regions, suggesting that both functions were encoded by this gene. It is proposed to designate this gene The deduced amino acid sequence of the product showed identity to PqqC of and Pqql of in the N-terminal region, and to PqqD of and Pqqll of in the C-terminal region. A fragment of AM1 DNA containing only produced a protein of 42 kDa in which corresponds to the size of the deduced amino acid sequence of PqqC/D, confirming the absence of a separate This genomic region complemented the growth of mutants of AM1 and DSM 760 on methanol. As previously reported for genes of a mutant of AM1 produced an intermediate of PQQ biosynthesis, which was converted to PQQ by incubation with a crude extract from cells expressing PqqC/D. The intermediate was found in both crude extract and culture supernatant, and it was purified from the crude extract. The PqqC/D enzyme reaction appeared to require molecular oxygen and reduced nicotinamide adenine dinucleotides.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error