A GH13 glycoside phosphorylase with unknown substrate specificity from Corallococcus coralloides

Abstract

Abstract Glycoside phosphorylases in subfamily GH13_18 of the carbohydrate-active enzyme database CAZy catalyse the reversible phosphorolysis of α-glycosidic bonds. They contribute to a more energy-efficient metabolism in vivo, and can be applied for the synthesis of valuable glucosides, sugars or sugar phosphates in vitro. Continuing our efforts to uncover new phosphorylase specificities, we identified an enzyme from the myxobacterium Corallococcus coralloides DSM 2259 that does not feature the signature sequence patterns of previously characterised phosphorylases. The enzyme was recombinantly expressed and subjected to substrate screening. Although it was confirmed that the Corallococcus phosphorylase does not have the same substrate specificity as other phoshorylases from subfamily GH13_18, its true natural substrate remains a mystery for now. Myxobacteria have been widely investigated as producers of numerous bioactive secondary metabolites for decades, but little research has been conducted on myxobacterial proteins. The present study exemplifies the untapped metabolic activities and functional diversity that these fascinating organisms may have left to show.