The TonB‐dependent uptake of pyrroloquinoline‐quinone (PQQ) and secretion of gluconate by Escherichia coli K‐12

What is it about?

Escherichia coli uses the redox cofactor pyrroloquinoline quinone (PQQ) from its environment to oxidise glucose with a glucose dehydrogenase in the periplasm to gluconate. The acid is secreted especially to solubilise phosphate salts under limiting conditions. The receptor PqqU (formerly YncD) in the outer membrane allows high affinity uptake of the rare vitamin like substance.

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