Isolation and composition of the constitutive agglutinins from haploid Saccharomyces cerevisiae cells.
Sex-specific agglutinins from the cell surface of haploid cells of Saccharomyces cerevisiae (X2180, mta and mt alpha) were purified and analysed. The constitutive agglutinin from mta cells was extractable with 3 mM dithiothreitol. It was shown to be a glycoprotein (3% mannose) with an apparent Mr of 43,000 based on gel filtration, but in SDS-PAGE it behaved as a much smaller molecule (Mr between 18,000 and 26,000). About one in three amino acids was a hydroxyamino acid. Its biological activity was resistant to boiling for 1 h, but sensitive to pronase. Intact mt alpha cells retained their agglutinability in the presence of dithiothreitol but limited trypsinizing released a biologically active agglutinin fragment. It had an apparent Mr of 320,000 (gel filtration). When analysed by SDS-PAGE, a single diffuse band with an apparent Mr of 225,000 was observed. The protein was 94% (w/w) mannose with a trace of N-acetyl glucosamine. Its biological activity was almost completely lost after boiling for 1 h. Both agglutinins behaved as monovalent molecules and specifically inhibited the biological activity of both noninduced and pheromone-induced cells. Pheromone treatment of mta cells resulted in an apparent 32-fold increase in agglutinin activity at the cell surface, whereas pheromone treatment of mt alpha cells only doubled the apparent agglutinin activity.
Sijmons
P C
PC
Department of Plant Physiology, University of Amsterdam, The Netherlands.
Nederbragt
A J
AJ
Klis
F M
FM
Van den Ende
H
H
D000373:Agglutinins / Q000032:analysis* / Q000302:isolation & purification; D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006238:Haploidy; D012441:Saccharomyces cerevisiae / Q000032:analysis* / Q000502:physiology
D000373:Agglutinins; D000596:Amino Acids