Abstract:
In this study, the pyrroloquinoline quinone (PQQ) high-yield mutant J1-1 of
Methylobacterium glucophilum MP688 was used to do bioinformatics analysis to extract the two methanol dehydrogenase (MDH) genes from the genome,
mpq0771 and
mpq2496. The effects of Ca
2+ and La
3+ on bacterial growth, PQQ synthesis, MDH expression, and enzyme activity were explored, as well as the roles of the two enzymes in methanol metabolism. The results showed that Ca
2+ and La
3+ both increased J1-1 bacteriophage growth and decreased PQQ synthesis in the context of fast viral development. In the presence of Ca
2+,
mpq0771 expression increased in strain J1-1. La
3+ inhibited
mpq0771 expression while promoting
mpq2496 expression and increasing total bacterial MDH viability. The knockout bacteria J1-1Δ
mpq0771 could not grow in methanol, but with the addition of La
3+, it could grow in methanol and synthesize PQQ, and MDH activity was identified. The product encoded by
mpq0771 was a Ca
2+-dependent MDH, and the product encoded by
mpq2496 was a La
3+-dependent MDH, and La
3+ could increase the production of mpq2496 and replace mpq0771 as a methanol dehydrogenase.