A proteomic analysis of secreted proteins from xylan-induced Bacillus sp strain K-1

The expression level of extracellular proteins in an alkaliphilic bacterium , Bacillus sp. strain K-1, grown in a xylan-containing medium, is significa ntly increased when compared with that grown in the nonxylan culture medium . A proteomic approach has been efficiently applied to separate and charact erize these differentially expressed secretory proteins. Eight prominent pr otein spots were identified and subjected to N-terminal amino acid sequenci ng. The results show that three spots share considerable similarity with th e xylanolytic enzymes and that two spots share considerable similarity with the GltC regulatory protein and 3-dehydroquinate dehydratase, respectively . In addition, the three other proteins show little similarity with the kno wn proteins in the database. In conclusion, our results demonstrate that th e proteomic approach is a highly efficient method to rapidly study the diff erential expression of the secreted proteins by Bacillus sp. strain K-l gro wn under xylan-induced condition.