Emily Boja National Heart, Lung and Blood Institute Office: 301-496-5628 FAX: 301-402-3404 E-mail: bojae@nhlbi.nih.gov Job Title: Staff Scientist Ph.D. in Protein Biochemistry/Enzymology from the Virginia Commonwealth University

Speaker: Emily Boja, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892

Topic: Structural Characterization and Post-Translational Processing of Mouse Zona Pellucida Glycoproteins Using Mass Spectrometry

Place: Building 549, Auditorium, NCI at Frederick, Frederick, MD

Time: Tuesday, April 8, 2003, at 2:00 PM

Abstract: Mass spectrometry has been widely used nowadays for protein identification and characterization of post-translational modifications of proteins, which serve biologically important functions. The zona pellucida is an extracellular matrix consisting of three major glycoproteins, ZP1, 2 and 3 that surrounds all mammalian eggs and mediates critical steps in fertilization and early development. All three zona proteins undergo extensive co- and post-translational modifications that play both structural and functional roles with respect to protein folding, secretion, assembly of a zona pellucida matrix, and sperm-egg binding. These modifications include cleavage of an N-terminal signal peptide, release of the mature protein ectodomain from a transmembrane domain by C-terminal processing, disulfide bond formation, and N- and O-linked glycosylation. Here we present some mass spectrometric data on the characterization of native zona pellucida glycoproteins directly isolated from mouse ovaries. We defined both amino and carboxyl termini of the mature zona proteins and characterized modifications including N-glycosylation sites and disulfide linkages.