Discovery and biochemical characterization of a mannose phosphorylase catalyzing the synthesis of novel β-1,3-mannosides

Abstract

Background: Mannoside phosphorylases are frequently found in bacteria and play an important role in carbohydrate processing. These enzymes catalyze the reversible conversion of β-1,2- or β-1,4-mannosides to mannose and mannose-1-phosphate in the presence of inorganic phosphate.

Methods: The biochemical parameters of this recombinantly expressed novel mannose phosphorylase were obtained. Furthermore purified reaction products were subjected to ESI- and MALDI-TOF mass spectrometry and detailed NMR analysis to verify this novel type of β-1,3-mannose linkage.

Results: We describe the first example of a phosphorylase specifically targeting β-1,3-mannoside linkages. In addition to mannose, this phosphorylase originating from the bacterium Zobellia galactanivorans could add β-1,3-linked mannose to various other monosaccharides and anomerically modified 5-bromo-4-chloro-3-indolyl-glycosides (X-sugars).

Conclusions: An unique bacterial phosphorylase specifically targeting β-1,3-mannoside linkages was discovered.

General significance: Functional extension of glycoside hydrolase family 130.

Keywords: Carbohydrate active enzyme; Enzymatic synthesis; Glycoside hydrolase family 130; Phosphorolysis; Zobellia galactanivorans; β-Mannan; β-Mannoside.