The Crystal Structure of OpeRATOR Reveals O-glycan Substrate Specificity
The O-glycoprotease OpeRATOR® from Genovis has spurred great interest from the community and has become a valuable tool for characterizing O-glycosylated biopharmaceuticals. Through a collaboration with the lab of Marcelo Guerin, the structure of OpeRATOR has now been solved and published in Nature Communications.
OpeRATOR originates from the commensal gut bacterium Akkermansia muciniphila, and as the name suggests this bacterium is capable of digesting mucins. The bacterium is associated with beneficial effects on health, likely through the regulation of the thickness of the mucus layer, a role in which the OpeRATOR enzyme may play a role.
In the paper, the high-resolution X-ray crystal structure of OpeRATOR is solved together with the ligated form to a glycopeptide substrate and the resulting product. The combined data set gives indications to the catalytic cycle and is complemented with glycopeptide chemistry and enzyme kinetics measurements to characterize the molecular mechanism and the substrate specificity. The structure and the kinetics data clearly shows that OpeRATOR digestion is occurring at sites modified with core 1 O-glycans and to a limited degree core 3 and α2,3 sialylated core 1 structures.
This new paper answers many questions regarding the specificities of the OpeRATOR O-glycoprotease and functional studies will provide further insights into the role of this enzyme in the host interactions of A. muciniphila. Meanwhile, the new findings in this paper make an important contribution to the application of this enzyme in analytical workflows for characterization of complex O-glycosylated biopharmaceuticals.
