Mannosidases capable of uncapping mannose-1-phospho-6-mannose linkages and demannosylating phosphorylated N-glycans and methods of facilitating mammalian cellular uptake of glycoproteins

摘要

The invention provides mannosidases capable of uncapping mannose-1-phospho-6-mannose moieties and demannosylating phosphorylated N-glycans, methods of using such mannosidases, glycoproteins produced using the methods, as well as methods of facilitating mammalian cellular uptake of glycoproteins.

主权项

1. A method of directing a glycoprotein to the interior of a mammalian cell, the glycoprotein comprising a mannose-1-phospho-6-mannose moiety, wherein the mannose residue that has a phosphate residue bound at the 6 position is linked to a terminal mannose residue at the 1 position of the terminal mannose residue, the method comprising contacting the cell with the glycoprotein after it has undergone:
(a) uncapping of the mannose-1-phospho-6-mannose moiety to mannose-6-phosphate on the glycoprotein; and (b) removal of the terminal mannose residue, wherein the glycoprotein that has undergone (a) and not (b) or (b) but not (a) does not substantially bind to a mannose-6-phosphate receptor on the cell, wherein the glycoprotein that has undergone (a) and (b) does substantially bind to a mannose-6-phosphate receptor on the cell, and wherein steps (a) and (b) are catalyzed by a single mannosidase enzyme that is a family 38 glycosyl hydrolase (GH38 family) mannosidase.