alfalfa plants inoculated with RmH580, a Sinorhizobium meliloti gcd mutant strain show a delay in nodule emergence and a reduced ability for nodulation at various inoculum dosages. Mutant RmH580 strain is also deficient in its competitive ability. In coinoculation experiments a mutant/wild-type inoculum ratio higher than 100:1 is necessary to obtain an equal ratio of nodule occupancy. PQQ-linked GCD is required by Sinorhizobium meliloti for optimal nodulation efficiency and competitiveness on alfalfa roots
enzymatic analysis of purified mGDH from cells defective in synthesis of ubiquinone and/or menaquinone reveal that quinone-free mGDH has very low levels of activity of glucose dehydrogenase and UQ2 reductase compared with those of ubiquinone-bearing mGDH, both activities are increased by reconstitution with ubuquinone1. mGDH utilizes both menaquinone and ubiquinone as a bound quinine. Bound menaquinone occurs in a fashion similar to that of bound ubiquinone in the mGDH molecule and functions as an electron acceptor from pyrrolo quinoline quinone
pulse radiolysis analysis reveal that the bound ubiquinone exists very close to pyrroloquinoline quinone at a distance of 11-13 A. Studies on mGDH mutants with substitutions for amino acid residues around pyrroloquinoline quinone show that Asp-466 and Lys-493, which are crucial for catalytic activity, interact with bound ubiquinone. It is proposed that the bound ubiquinone is involved in the catalytic reaction in addition to the intramolecular electron transfer in mGDH
multiple genetic loci involved in quinoprotein glucose dehydrogenase activity are required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. The enzymatic products of GDH activity are involved in the inhibitory effect. D-Glucono-1,5-lactone and D-gluconic acid, but not D-gluconate, are able to inhibit prodigiosin production. Oxidation of D-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon
enzymatic analysis of purified mGDH from cells defective in synthesis of ubiquinone and/or menaquinone reveal that quinone-free mGDH has very low levels of activity of glucose dehydrogenase and UQ2 reductase compared with those of ubiquinone-bearing mGDH, both activities are increased by reconstitution with ubuquinone1. mGDH utilizes both menaquinone and ubiquinone as a bound quinine. Bound menaquinone occurs in a fashion similar to that of bound ubiquinone in the mGDH molecule and functions as an electron acceptor from pyrrolo quinoline quinone
multiple genetic loci involved in quinoprotein glucose dehydrogenase activity are required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. The enzymatic products of GDH activity are involved in the inhibitory effect. D-Glucono-1,5-lactone and D-gluconic acid, but not D-gluconate, are able to inhibit prodigiosin production. Oxidation of D-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon