Structure and functional properties of the Bacillus subtilis transcriptional repressor Rex.
The transcription factor Rex has been implicated in regulation of the expression of genes important for fermentative growth and for growth under conditions of low oxygen tension in several Gram-positive bacteria. Rex senses the redox poise of the cell through changes in the NADH/NAD(+) ratio. The crystal structures of two essentially identical Rex proteins, from Thermus aquaticus and T. thermophil