BMB Section Seminar: "Large-scale intact glycopeptide identification by Mascot database search"
Dr. Ravi Chand Bollineni, Thiede group, Section for Biochemistry and Molecular Biology, Department of Biosciences, UiO
Illustration: Ravi C. Bollineni
Protein glycosylation is one of the most common and highly heterogeneous posttranslational modification. Despite the high throughput advancements, glycoproteome profiling using mass spectrometry (MS) still remains a challenging task. High-throughput intact glycopeptide analysis is challenged by their detection in MS and annotation by computational tools. In this seminar, I will present an approach for automated annotation of intact glycopeptide mass spectra. The steps in adopting the Mascot search engine for intact glycopeptide analysis included: i) assigning one letter codes for monosaccharides, ii) linearizing glycan sequences and iii) preparing custom glycoprotein databases. Automated annotation of both N- and O-linked glycopeptides was proven using standard glycoproteins. In a large-scale study of serum glycoproteins, a total of 257 glycoproteins containing 970 unique glycosylation sites and 3447 non-redundant N-linked glycopeptide variants were identified. This represents a single tool, that collectively allows the i) elucidation of N- and O-linked glycopeptide spectra, ii) matching glycopeptides to known protein sequences, and iii) high-throughput, batch-wise analysis of large-scale glycoproteomics data sets.