Structures of the Porphyromonas gingivalis OxyR regulatory domain explain differences in expression of the OxyR regulon in Escherichia coli and P. gingivalis

Differences in OxyR regulated expression of oxidative stress genes between Escherichia coli and Porphyromonas gingivalis are explained by very minor differences in structure and amino-acid sequence of the respective oxidized and reduced OxyR regulatory domains. These differences affect OxyR quaternary structures and are predicted from model building of full length OxyR-DNA complexes to confer distinct modes of DNA binding on this transcriptional regulator.