Extended Data Figure 4. Identification of CD18.
A. The spectrum of one of the CD18 peptides obtained by nanospray-ion trap tandem mass spectrometry. B. The deconvoluted MS/MS spectrum of tryptic peptide NVTR with 3 HexNAc. M: the parent ion of NVTR-HexNAc(3) at m/z 549.760 Da. M-18: loss one H2O in NVTR-HexNA(3). a2: the observed m/z 186.1218 Da matched to the a2 ion. y1: the observed m/z 175.1261 Da matched to the y1 ion. C. The crystal structure of LFA-1 headpiece (5E6U.pbd). The region encircled by dots from the left view is enlarged (right), representing the O-glycosylation on Thr256 in βI-domain.