Catalyzes the coenzyme F420-dependent oxidation of glucose 6-phosphate (G6P) to 6-phosphogluconolactone. Appears to have a role in resistance to oxidative stress, via its consumption of G6P that serves as a source of reducing power to combat oxidative stress in mycobacteria. D-glucose 6-phosphate + H(+) + oxidized coenzyme F420-(gamma-L-Glu)(n) = 6-phospho-D-glucono-1,5-lactone + reduced coenzyme F420-(gamma-L-Glu)(n) Homodimer. Belongs to the F420-dependent glucose-6-phosphate dehydrogenase family.