Mona SchulteUniversity of Münster Institute for Hygiene Biomedical Mass Spectrometry 48149-Münster, Germany |
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| Email: Net: |
mona.schulte@uni-muenster.de http://www.campus.uni-muenster.de/hyg_forsch_dreisewerd.html |
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Identification and characterization of glycoconjugates in complex biological systems as ligands for lectins and determination of their binding properties
The mass spectrometric characterization of molecular structures of proteins and glycoconjugates acting as binding partners is considered as an essential prerequisite for the understanding of cellular interactions and recognition processes and thus plays an essential role in life sciences. The determination of the binding properties of both host and ligand therefore represents an elusive goal.
Within this PhD project, carbohydrate components such as oligosaccharides, glycolipids and glycoproteins serving as binding partners for carbohydrate-binding proteins, e.g. lectins will be identified and thoroughly characterized. Furthermore, lectins representing hosts for glycoconjugates will be isolated from raw biological material and analyzed. Functional proteins will be studied with respect to their amino acid sequence and various posttranslational modifications. In collaboration with Siva Kumar a lactose-specific lectin was isolated from crude protein extracts of the freshwater mussel Lamellidens corrianus. The lectin obtained was further analyzed by SDS-PAGE under reducing conditions, followed by excision of distinct gel bands and tryptic in-gel digestion. MS analysis of proteolytic peptides was performed on a nanoESI Q-ToF mass spectrometer using low-energy CID. So far, parts of the primary structure of the lectin were obtained by de novo sequencing. Furthermore, the glycan profiles were analyzed to gain an insight into the complexity of glycosylation of the three protein species. Tandem MS experiments of glycopeptide ions revealed the presence of an N-glycan modification which has not been reported for a protein from a bivalvia species, so far. Another project aims at the characterisation of a galactose-specific lectin from the extracts of Trichosanthes dioica seeds in close collaboartion with the group of Swamy. Lectin -carbohydrate complexes will be probed by means of Q-TOF-MS and high resolution FT-ICR-MS. Various activation methods such as electron capture dissociation (ECD), infrared multiphoton dissociation (IRMPD) and low-energy collision induced dissociation (CID) will be applied to obtain comprehensive structural information.
Last update: 29.04.2013
