Fig 1. Organisation of the cydWAB genes.

(A) Map of cydWAB operon and the positions of primers used for PCR. To construct the cydAB mutant used in this study, a DNA fragment containing part of both cydA and cydB (in grey) was deleted. (B) PCR performed on cDNA obtained by reverse transcription on total RNA extract from P. gingivalis ATCC 33277 (WT), cydAB mutant (Δ) and complemented mutant (C). H₂O and genomic DNA of P. gingivalis ATCC 33277 were used as controls.