A novel Mucin-selective protease StcE is a powerful tool for heavily O-glycosylated mucin proteins MS analysis

Mucins, major components of the extracellular mucus are a family of high molecular weight, heavily glycosylated proteins. In most animals these proteins are produced by epithelial tissues and used as biomarkers for abnormal conditions such as ovarian and lung cancers. Mucins consist of a polypeptide backbone of hundreds to thousands of amino acids, the glycosylation of the mucins can contribute to over 50% of the total protein mass. Mucin domains are notable for their high frequency of Ser (S) and Thr (T) residues which are O-glycosylated with
α-N-acetylgalactosamine (α-GalNAc). This leads to dynamic and very heterogenous glycoprotein populations which cannot be predicted from genomic information only. Investigating biological functions of mucins at the molecular level is a challenge, as only few tools are available to probe mucin domains.

The secreted protease of C1 esterase inhibitor (StcE) from Escherichia coli (O157:H7) is a mucin specific bacterial metalloprotease that recognizes a specific consensus sequence and cleaves the mucin polypeptide proximal to an O-glycosylated serine or threonine. Thus, the Mucin-selective proteolysis by StcE, is a novel and a powerful tool for the study of mucin domain structure and function.

This product development is conducted under license from the lab of Prof. Caroline Bertozzi lab at the Stanford university.