The Yeast That Had Human-Like Chemicals

The Transformation by a Magical Spell of Glycotechnology

Abstract

Our principal goal was the molecular breeding of yeasts able to produce human-type sugar chains and which could be used for pharmaceutical production. This ambitious project was carried out in conjunction with two other short-and mediumterm supporting sub-projects.
The short-term project lasted approximately two years and involved the development of tools for Glycobiology. The initial step involved determining the sequence of one “Mucin box”, necessary for formation of mucin-type sugar chains. Subsequently, we cloned the gene for Endoglycosidase M, an enzyme that catalyzes transglycosylation and established largescale preparation of the recombinant enzyme. We succeeded in creating a novel RNase with complex-type sugar chains instead of the original high-mannose type sugar chains generated in vitro.
The theme of the medium-term project, involved the purification of the enzyme GnT-IV glycosyltransferase, which is closely associated with the activity of glycoprotein. We proceeded to clone the gene for this enzyme and discovered, to our surprise, that two types of genes exist for GnT-IV glycosyltransferase.