Further characterization of the saccharide specificity of peanut (Arachis hypogaea) agglutinin.
2-Dansylamino-2-deoxy-D-galactose (GalNDns) has been shown to bind to peanut (Arachis hypogaea) agglutinin (PNA) in a saccharide-specific manner. This binding was accompanied by a five-fold increase in the fluorescence of GalNDns. The interaction was characterized by an association constant of 0.15 mM at 15 degrees and delta H and delta S values of -57.04 kJ.mol-1 and -118.1J.mol-1.K-1, respectively. Binding of a variety of other mono-, di- and oligo-saccharides to PNA, studied by monitoring their ability to dissociate the PNA GalNDns complex, revealed that PNA interacts with several T-antigen-related structures, such as beta-D-Galp-(1----3)-D-GalNAc, beta-D-Galp-(1----3)-alpha-D-GalpNAcOMe, and beta-D-Galp-(1----3)-alpha-D-GalpNAc-(1----3)-Ser, as well as the asialo-GM1 tetrasaccharide, with comparable affinity, thus showing that this lectin does not discriminate between saccharides in which the penultimate sugar of the beta-D-Galp-(1----3)-D-GalNAc unit is the alpha or beta anomer, in contrast to jacalin (Artocarpus integrifolia agglutinin), another anti T-lectin which preferentially binds to beta-D-Galp-(1----3)-alpha-D-GalNAc and does not recognize beta-D-Galp-(1----3)-beta-D-GalNAc or the related asialo-GM1 oligosaccharide. These studies also indicated that, in the extended combining region of PNA which accommodates a disaccharide, the primary subsite (subsite A) is highly specific for D-galactose, whereas the secondary subsite (subsite B) is less specific and can accommodate various structures, such as D-galactose, 2-acetamido-2-deoxy-D-galactose, D-glucose, and 2-acetamido-2-deoxy-D-glucose.
Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
M J
MJ
Swamy
D
D
Gupta
S K
SK
Mahanta
A
A
Surolia
D010367:Arachis; D001665:Binding Sites; D002240:Carbohydrate Sequence; D007700:Kinetics; D037102:Lectins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000737:chemistry / Q000378:metabolism; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D019887:Peanut Agglutinin; D037121:Plant Lectins
D037102:Lectins; D009005:Monosaccharides; D009844:Oligosaccharides; D019887:Peanut Agglutinin; D037121:Plant Lectins