Recombinant prespore-specific antigen from Dictyostelium discoideum is a beta-sheet glycoprotein with a spacer peptide modified by O-linked N-acetylglucosamine

Eur J Biochem. 1996 Jun 1;238(2):511-8. doi: 10.1111/j.1432-1033.1996.0511z.x.


Prespore-specific antigen (PsA) is a putative cell-adhesion molecule of the cellular slime mould Dictyostelium discoideum, which has a similar molecular architecture to several mammalian cell-surface proteins. It has an N-terminal globular domain presented to the extracellular environment on an O-glycosylated stem (glycopeptide) that is attached to the cell membrane through a glycosyl-PtdIns anchor. The sequence of PsA suggests that PsA may belong to a new family of cell-surface molecules and here we present information on the structure of the N-terminal globular domain and determine the reducing-terminal linkage of the O-glycosylation. To obtain a sufficient amount of pure protein, a secreted recombinant form of PsA (rPsA), was expressed in D. discoideum and characterised. 1H-NMR spectra of rPsA contained features consistent with a high degree of beta-sheet in the N-terminal globular domain, a feature commonly observed in cell-adhesion proteins. Solid-phase Edman degradation of the glycopeptide of rPsA indicated that 14 of the 15 threonines and serines in the spacer region were glycosylated. The chemical structures of the O-glycosylations were determined to be single N-acetylglucosamine residues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylglucosamine / analysis
  • Amino Acid Sequence
  • Animals
  • Antigens, Protozoan*
  • Antigens, Surface / chemistry*
  • Antigens, Surface / genetics
  • Carbohydrate Conformation
  • Chromatography, Gas
  • Chromatography, High Pressure Liquid
  • Dictyostelium / chemistry*
  • Fungal Proteins / chemistry*
  • Fungal Proteins / genetics
  • Glycopeptides / chemistry
  • Glycosylation
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / genetics
  • Molecular Sequence Data
  • Protein Structure, Secondary*
  • Protozoan Proteins*
  • Recombinant Proteins / chemistry
  • Sequence Homology, Amino Acid
  • Trypsin / metabolism


  • Antigens, Protozoan
  • Antigens, Surface
  • Fungal Proteins
  • Glycopeptides
  • Membrane Glycoproteins
  • Protozoan Proteins
  • Recombinant Proteins
  • prespore-specific antigen, Dictyostelium discoideum
  • Trypsin
  • Acetylglucosamine