Species of family Promicromonosporaceae and family Cellulomonadeceae that produce cellulosome-like multiprotein complexes.

OBJECTIVES: To screen the phylogenetically-nearest members of Cellulosimicrobium cellulans for the production of cellulosome-like multienzyme complexes and extracellular ß-xylosidase activity against 7-xylosyltaxanes and to get corresponding molecular insights. RESULTS: Cellulosimicrobium (family Promicromonosporaceae) and all genera of the family Cellulomonadeceaec produced both cellulosome-like multienzyme complexes and extracellular ß-xylosidase activity, while the other genera of the family Promicromonosporaceae did not. Multiple sequence alignments further indicated that hypothetic protein M768_06655 might be a possible key subunit. CONCLUSION: This is the first report that many actinobacteria species can produce cellulosome-like multienzyme complexes. The production of cellulosome-like complexes and the extracellular ß-xylosidase activity against 7-xylosyltaxanes might be used to differentiate the genus Cellulosimicrobium from other genera of the family Promicromonosporaceae.