Engineered bacteria churn out cancer biomarkers

Aravind publishes his work on a novel synthetic glycobology approach for producing O-linked glycoproteins using lab strains of bacteria equipped with glycosylation machinery

Our exciting new work on engineering an orthogonal O-glycan biosynthesis system to support the production of O-linked glycoproteins was published today in the October issue of Nature Chemical Biology.

The study, lead by Aravind Natarajan, now a postdoc in the Bhatt lab at Stanford, describes the creation of a set of orthogonal pathways for eukaryotic O-linked protein glycosylation in Escherichia coli that installed the cancer-associated mucin-type glycans Tn, T, sialyl-Tn and sialyl-T onto serine residues in acceptor motifs derived from different human O-glycoproteins. These same glycoengineered bacteria were used to supply crude cell extracts enriched with glycosylation machinery that permitted cell-free construction of O-glycoproteins in a one-pot reaction. In addition, O-glycosylation-competent bacteria were able to generate an antigenically authentic Tn-MUC1 glycoform that exhibited reactivity with antibody 5E5, which specifically recognizes cancer-associated glycoforms of MUC1. We anticipate that the orthogonal glycoprotein biosynthesis pathways developed in this work will provide facile access to structurally diverse O-glycoforms for a range of important scientific and therapeutic applications. The research was supported by the Defense Threat Reduction Agency, the National Science Foundation, the National Institutes of Health and the Cornell Center on the Physics of Cancer Metabolism. The researchers made use of the Cornell Institute of Biotechnology, where DeLisa serves as director.