Endothelial Galectin-1 Binds to Specific Glycans on Nipah Virus Fusion Protein and Inhibits Maturation, Mobility, and Function to Block Syncytia Formation
Figure 6
The F3 N-glycan on NiV-F is a complex N-glycan containing putative binding sites for galectin-1.
A, MALDI-TOF mass spectrum of all permethylated N-glycans from NiV-F0. Annotated structures were deduced by taking into account theoretical compositions and knowledge of the biosynthetic pathways (for further information, refer to http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.TOC&depth=2). All molecular ions are [M+Na]+. Peaks labeled with * represent contaminating hexose polymers. Unlabelled peaks are non-carbohydrate contaminants or permethylation products. B, Glycan component of the F3 glycopeptide, GALEIYKNNTHDLVGDVR, and effect of sialidase S digestion. Top panel – NiV-F0 was digested with trypsin and the peptide/glycopeptide mixture was analysed by LC-ES-MS/MS; the summed MS data for the F3 glycopeptide are shown. Bottom panel – The LC-ES-MS/MS experiment was repeated after treatment of the tryptic digest of NiV-F0 with Sialidase S; summed MS data for the partially desialylated F3 glycopeptide are shown. Unannotated peaks correspond to peptides. Molecular ions attributable to glycopeptides are annotated with m/z values and subscripted charge states. Peaks labeled in bold correspond to molecular ions that have shifted on Sialidase S digestion; these peaks are also assigned a potential glycan structure. Symbol nomenclature is that used by the Consortium of Functional Glycomics (CFG) (see key below). See also Figure S2. Key: Galactose (yellow circle), Mannose (green circle), GlcNAc (blue square), Fucose (red triangle), NeuAc, (purple diamond).