Nucleotide sequence of a 13-1,3-glucanase Isoenzyme II(A) gene of Oerskovia xanthineolytica LL G109 (Cellulomonas cellulans) and initial characterization of the recombinant enzyme expressed in Bacillus subtilis

Abstract

The nucleotide sequence of the βgIII(A) gene, encoding the extracellular β-1,3-glucanase II(A) (βgIII(A)) of the yeast-lytic actinomycete Oerskovia xanthineolytica LL G109, was determined. Sequence comparison shows that the βgIII(A) enzyme has over 80% identity to the βgIII isoenzyme, an endo-β- 1,3-glucanase having low yeast-lytic activity secreted by the same bacterium. The βgIII(A) enzyme lacks a glucan- or mannan-binding domain, such as those observed in β-1,3-glucanases and proteases having high yeast/fungus-lytic activity. It can be included in the glycosyl hydrolase family 16. Gene fusion expression in Bacillus subtilis DN1885 followed by preliminary characterization of the recombinant gene product indicates that βgIII(A) has a p1 of 3.8 to 4.0 and is active on bOth laminarin and curdlan, having an acid optimum pH activity (ca. 4.0).