FIGURE 4.

Repeat nano-LC-MS/MS of PNGase F-deglycosylated trypsin-digested mammalian rLILRA3 confirmed all five predicted N-glycosylation sites. In-gel peptide digestion of deglycosylated rLILRA3 with trypsin showed deamidation of asparagine to aspartic acid at Asn¹⁴⁰ (A), Asn²⁸¹ (B), Asn³⁰² (C), Asn³⁴¹ (D), and Asn⁴³¹ (E) indicating N-linked glycosylation of these sites. The sequence of the peptide, the fragmentation pattern, and the detected fragment ions are shown at the top right in each panel. b ions contain the N-terminal region of the peptide; y ions contain the C-terminal region of the peptide. Deamidation of asparagine to aspartic acid is designated as “N” with an underscore.