ABSTRACT
The present paper describes the purification and function of a haemagglutinin from the amoebocyte lysate of the horseshoe crab Carcinoscorpius rotundicauda. The purified protein consisted of a single subunit of Mr 24 000 and agglutinated human blood-group-A+ erythrocytes. Its haemagglutinin activity was inhibited by purified lysate, coagulogen, but not by sugars. The haemagglutinin differed immunologically and in activity from the sialic-acid-binding lectin carcinoscorpin present in the haemolymph. It caused aggregation of forma-fixed amoebocytes, and on the basis of this observation its role in cell-cell adhesion is proposed. This new haemagglutinin promotes cell-cell aggregation in amoebocytes in a manner that shares some similarities with thrombospondin-mediated platelet aggregation in vertebrates [Jaffe, Leuang, Nachman, Levin & Moseher (1981) Nature (London) 295, 246-248].
Subject(s)
Hemagglutinins/isolation & purification , Horseshoe Crabs/metabolism , Amino Acids/analysis , Animals , Brachyura/cytology , Cell Aggregation/drug effects , Chromatography, Gel , Electrophoresis, Polyacrylamide Gel , Erythrocyte Aggregation/drug effects , Hemagglutinins/pharmacology , Microscopy, Phase-Contrast , Spectrophotometry, UltravioletABSTRACT
The ADP-ribosyltransferase activity of the A1 subunit of cholera toxin is specifically inhibited by the dye cibacron blue 3GA. The presence of a 'dinucleotide fold' in the A1 subunit is thus established for the first time. This specific inhibition observed in vitro is successfully exploited in vivo for the inhibition of te diarrheal response brought out by the pure toxin in the rabbit ileal-loop test.
Subject(s)
Cholera Toxin/antagonists & inhibitors , Nucleotidyltransferases/antagonists & inhibitors , Oligonucleotides , Triazines/pharmacology , Animals , Binding, Competitive , Biological Assay , Cholera Toxin/pharmacology , Dinucleoside Phosphates , Female , Ileum/drug effects , NAD/metabolism , Poly(ADP-ribose) Polymerases , Protein Conformation , RabbitsSubject(s)
Sialoglycoproteins/isolation & purification , Alkaline Phosphatase/isolation & purification , Animals , Brain/enzymology , Chromatography, Affinity/methods , Horseshoe Crabs , Isoenzymes/isolation & purification , Lectins , Sheep , Sialic Acid Binding Immunoglobulin-like Lectins , alpha-Fetoproteins/isolation & purificationSubject(s)
Horseshoe Crabs/analysis , Lectins/analysis , Sialic Acids/analysis , Amino Acids/analysis , Animals , Carbohydrates/analysis , Chemical Phenomena , Chemistry , Hydrolysis , Lectins/isolation & purification , Peptides/analysis , Proteins/analysis , Sialic Acid Binding Immunoglobulin-like Lectins , Sialic Acids/isolation & purificationABSTRACT
A sialic acid-binding lectin, carcinoscorpin, has been purified to apparent homogeneity in 40% yield from the Indian horseshoe carb, Carcinoscorpius rotunda cauda. This glycoprotein lectin of molecular weight 420,000 was composed of two non-identical subunits of molecular weights 27,000 and 28,000 as determined by gel electrophoresis in the presence of sodium dodecyl sulfate. The hemagglutination activity of the lectin was susceptible to guanidine-HCl; modification of tyrosyl and tryptophanyl residues also inhibited the activity although alkylation of the -SH group, reduction of disulfide bonds or modification of amino and carboxyl groups were without any effect. The monomeric form of the lectin produced by succinylation of native protein was inactive in binding to sialoglycoconjugates.
