Structure of the acidic N-linked carbohydrate chains of the 55-kDa glycoprotein family (PZP3) from porcine zona pellucida.
N-linked carbohydrate chains of the major 55-kDa family, PZP3, of porcine zona pellucida glycoproteins are composed of neutral (28%) and acidic (72%) complex-type chains. The structures of the main components of the neutral chain have been established [Noguchi, S., Hatanaka, Y., Tobita, T. & Nakano, M. (1992) Eur. J. Biochem. 204, 1089-1100]. Here we report the structures of the acidic chains. Only two kinds of acidic fragments were released from PZP3 by endo-beta-galactosidase digestion following beta-elimination of O-linked chains. 500-MHz one-dimensional and two-dimensional 1H-NMR spectroscopy revealed their structures to be Sia alpha(2-3)Gal beta(1-4) [HSO3-6]GlcNAc beta(1-3)Gal and HSO3-6GlcNAc beta(1-3)Gal, showing that the sulfate-containing acidic chains are constructed with non-branched N-acetyllactosamine repeats which have sialic acid(s) at the non-reducing end(s) and sulfate at the C-6 position of GlcNAc residues. The acidic N-linked chains obtained from PZP3 by hydrazinolysis were separated into diantennary chains (34%) and tri- and tetra-antennary chains (66%) by concanavalin-A--agarose gel chromatography. The diantennary chains and their sialidase digests were fractionated by DEAE-HPLC. From the analyses of the endo-beta-galactosidase digests of each fraction, structures of the diantennary acidic chains were determined. They are classified into four groups. The first group is the sialylated chains without the sulfated N-acetyllactosamine repeating unit. The other three groups have the chains of various lengths differing in the number of monosulfated N-acetyllactosamine unit. These chains are extended from the Man alpha(1-3) branch of the trimannosyl core in the second group, from the Man alpha(1-6) branch in the third group, and from both branches in the fourth group. The structural features of the tri- and tetra-antennary acidic chains are also presented.
Noguchi
S
S
Graduate School of Science and Technology, Chiba University, Japan.
Nakano
M
M
D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004527:Egg Proteins; D005260:Female; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011956:Receptors, Cell Surface; D013552:Swine; D015044:Zona Pellucida / Q000737:chemistry*; D000072216:Zona Pellucida Glycoproteins
D002241:Carbohydrates; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins