3-O-α-d-Glucopyranosyl-l-rhamnose phosphorylase from Clostridium phytofermentans
摘要:
We found an unreported activity of phosphorylase catalyzed by a protein (Cphy1019) belonging to glycoside hydrolase family 65 (GH65) from Clostridium phytofermentans. The recombinant Cphy1019 produced in Escherichia coli did not phosphorolyze alpha-linked glucobioses, such as trehalose (alpha 1-alpha 1), kojibiose (alpha 1-2), nigerose (alpha 1-3), and maltose (alpha 1-4), which are typical substrates for GH65 enzymes. In reverse phosphorolysis, Cphy1019 utilized only L-rhamnose as the acceptor among various sugars examined with beta-D-glucose 1-phosphate as the donor. The reaction product was determined to be 3-O-alpha-D-glucopyranosyl-L-rhamnose, indicating strict alpha 1-3 regioselectivity. We propose 3-O-alpha-D-glucopyranosyl-L-rhamnose: phosphate beta-D-glucosyltransferase as the systematic name and 3-O-alpha-D-glucopyranosyl-L-rhamnose phosphorylase as the short name for this novel GH65 phosphorylase. (C) 2011 Elsevier Ltd. All rights reserved.