AxyR, an AraC Family Transcriptional Activator of the Xylanase 3 Gene, Requires Xylo-Oligosaccharides as a Cofactor for DNA Binding in Paenibacillussp. Strain W-61

The xylanolytic bacterium Paenibacillussp. strain W-61 encodes three extracellular xylanase genes, xyn1, xyn3, and xyn5. In this study, we identified a transcriptional activator required for transcription of the xyn3gene in strain W-61. The activator, AxyR, contained the highly homologous AraC-type DNA binding domain and required xylobiose, xylotriose, or xylotetraose as cofactor for binding to the xyn3promoter region.