Fig. 3: Density mapping and distribution preference of O-glycosites in mouse testes.

a, b The number of unambiguous O-glycosites per peptide (a) and per protein (b). Glycoproteins involved in spermatogenesis and fertilization were labeled red. c The number of unique O-glycopeptides and GPSM per protein. The glycoproteins with a high number of glycopeptides (≥ 5) and high abundance of GPSM (> 100) were labeled in red. d Twenty glycopeptides with dense O-glycosites (≥ 5) were listed, and the tissue specificity of the corresponding proteins was shown with reference to the UniProt database. The histogram shows the number of GPSM of these glycopeptides identified in each group. e The protein domains containing O-glycosites located at the outer or inner edges (≥  2 sites) were shown. The domain edge is defined as 20 amino acids located inside (inner edge, positive) or outside (outer edge, negative) the N-/C-terminal of the domain. f A region near the N-terminal of domain peptidase S1 domain was found to be susceptible to O-glycosylation. The glycosites identified in testes of 24-day-old and 12-week-old mice are indicated by yellow and orange boxes, respectively. g An illustrative annotated MS2 spectrum of the O-glycopeptide from PRSS43 modified with T structure [Hex(1)HexNAc(1)] was shown. h Summary of distribution percentage of 799 O-glycosites identified in mouse testes. Protein annotations were referred against the UniProt database. GPSM glycopeptide-spectrum matches, VVA vicia villosa agglutinin, PNA peanut agglutinin. Source data are provided as a Source Data file.