Priming mass spectrometry-based sulfoglycomic mapping for identification of terminal sulfated lacdiNAc glycotope.
In an effort to prime our mass spectrometry (MS)-based sulfoglycomic mapping platform technology for facile identification of sulfated lacdiNAc (GalNAcβ1-4GlcNAcβ1-), we have re-examined the N-glycans of bovine thyroid stimulating hormone. We showed that MALDI-MS mapping of permethylated glycans in negative ion mode can give an accurate representation of the sulfated glycans and, through MS/MS, diagnostic ions can be derived that we can collectively define the presence of a terminal sulfated lacdiNAc moiety at high sensitivity. Based on these ions, which can also be produced by nanoESI-MS(n), we demonstrated that the glycome of an ovarian carcinoma cell line, RMG-1, comprises a high abundance of sulfated lacdiNAc epitopes carried on multiantennary complex type N-glycans alongside fucosylated, sialylated and/or sulfated lacNAc antennae. This represents the first report of a natural glycomic occurrence of sulfated lacdiNAc on a cell line, as opposed to other better-characterized presence on secreted glycoproteins from a handful of sources. It is anticipated that with improved methods of detection such as that developed in this work, we are likely to identify a wider occurrence of sulfated lacdiNAc and be able to more accurately delineate the regulatory mechanism dictating the choice of a cell type in synthesizing sulfated, sialylated, fucosylated and/or non-substituted lacdiNAc.
Institute of Biological Chemistry, Academia Sinica, 128, Academia Road Sec 2, Nankang, Taipei 115, Taiwan.
Shin-Yi
SY
Yu
Lan-Yi
LY
Chang
Chu-Wen
CW
Cheng
Chi-Chi
CC
Chou
Michiko N
MN
Fukuda
Kay-Hooi
KH
Khoo
D000818:Animals; D002417:Cattle; D007785:Lactose / Q000031:analogs & derivatives* / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013972:Thyrotropin / Q000737:chemistry
C093701:N-acetylgalactosaminyl-1-4-N-acetylglucosamine; D013972:Thyrotropin; D007785:Lactose