Glyco

Title : Structural characterization of native mouse zona pellucida proteins using mass spectrometry

Abstract :

The zona pellucida is an extracellular matrix consisting of three glycoproteins that surrounds mammalian eggs and mediates fertilization
The primary structures of mouse ZP1 , ZP2 , and ZP3 have been deduced from cDNA
Each has a predicted signal peptide and a transmembrane domain from which an ectodomain must be released
All three zona proteins undergo extensive co- and post-translational modifications important for secretion and assembly of the zona matrix
In this report, native zonae pellucidae were isolated and structural features of individual zona proteins within the mixture were determined by high resolution electrospray mass spectrometry
Complete coverage of the primary structure of native ZP3 , 96% of ZP2 , and 56% of ZP1 , the least abundant zona protein , was obtained
Partial disulfide bond assignments were made for each zona protein , and the size of the processed, native protein was determined
The N termini of ZP1 and ZP3 , but not ZP2 , were blocked by cyclization of glutamine to pyroglutamate
The C termini of ZP1 , ZP2 , and ZP3 lie upstream of a dibasic motif , which is part of, but distinct from, a pro protein convertase cleavage site
The zona proteins are highly glycosylated and 4/4 potential N-linkage sites on ZP1 , 6/6 on ZP2 , and 5/6 on ZP3 are occupied
Potential O-linked carbohydrate sites are more ubiquitous, but less utilized

Output (sent_index, trigger, protein, sugar, site):

Output(Part-Of) (sent_index, protein, site):

*Output_Site_Fusion* (sent_index, protein, sugar, site):