Structure of the O-linked carbohydrate chains of porcine zona pellucida glycoproteins.
The N-linked carbohydrate chains of porcine zona pellucida glycoproteins were released by digestion with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and subsequently separated from the O-glycoprotein by gel-permeation chromatography on Bio-Gel P-100. The O-linked carbohydrate chains were released from the O-glycoprotein by alkaline borohydride treatment. Fractionation of the extremely heterogeneous mixture of O-linked oligosaccharide alditols was achieved by a combination of chromatographic techniques comprising gel-permeation chromatography on Bio-Gel P-4 and P-6, anion-exchange FPLC on Mono Q, and high-pH anion-exchange chromatography on CarboPac PA-1. The primary structures of 32 O-glycans were determined by one- and two-dimensional 1H-NMR spectroscopy. The major part of the analyzed compounds contain a combination of the structural elements Gal beta 1-4GlcNAc beta 1-3Gal beta 1-3GalNAc-ol, Gal beta 1-4(6SO4-)GlcNAc, and alpha 2-3-linked Neu5Gc or Neu5Ac. This series of compounds has the following structure, where n = 0 to > 6: [Neu5Gc/Ac alpha2-3]0-1[Gal beta 1-4(6SO4-)GlcNAc beta 1-3]nGal beta 1-4GlcNAc beta 1-3Gal Beta 1-3GalNAc-ol. In addition, smaller compounds were identified in which the Gal beta 1-3GalNAc-ol core is substituted by Neu5Gc/Ac alpha 2-6-linked to GalNAc-ol and/or Neu5Gc/Ac alpha 2-3-linked to Gal. Furthermore, oligosaccharides were obtained in which the distribution of 6-O-sulfated GlcNAc residues differs from that in the above-mentioned general structure, and a small portion of the oligosaccharides has the GlcNAc beta 1-3GalNAc-ol core structure. Analysis of the endo-beta-galactosidase digests of pools of N- and O-glycans indicated that the two types of oligosaccharides contain qualitatively similar poly(N-acetyllactosamine) chains. In the case of the N-linked carbohydrate chains, multiple branching of the core structures occurs, resulting in an even larger heterogeneity than observed for the O-linked carbohydrate chains.
Hokke
C H
CH
Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
Damm
J B
JB
Penninkhof
B
B
Aitken
R J
RJ
Kamerling
J P
JP
Vliegenthart
J F
JF
D000818:Animals; D000838:Anions; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006023:Glycoproteins / Q000737:chemistry*; D006026:Glycoside Hydrolases; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid; D012794:Sialic Acids / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D013552:Swine; D015044:Zona Pellucida / Q000737:chemistry*; D001616:beta-Galactosidase / Q000378:metabolism
D000838:Anions; D002241:Carbohydrates; D006023:Glycoproteins; D012794:Sialic Acids; D013431:Sulfates; D006026:Glycoside Hydrolases; C026093:keratan-sulfate endo-1,4-beta-galactosidase; D001616:beta-Galactosidase; D019158:N-Acetylneuraminic Acid