Structure of mannose-specific snowdrop (Galanthus nivalis) lectin is representative of a new plant lectin family.
Tetrameric Galanthus nivalis agglutinin (50,000 M(r)) belongs to a super-family of alpha-D-mannose-specific plant bulb lectins known to be potent inhibitors of retroviruses. The 2.3 A crystal structure of this lectin complexed with methyl alpha-D-mannose reveals a novel three-fold symmetric beta-sheet polypeptide fold. Three antiparallel four-stranded beta-sheets, each with a conserved mannose-binding site, are arranged as a 12-stranded beta-barrel. The tetramer displays 222 symmetry. Pairs of monomers form stable dimers through C-terminal strand exchange. The so formed hybrid beta-sheets are the sites for high affinity mannose binding in the dimer interface. Occupancy observed at corresponding sites in other beta-sheets suggests a potential for twelve sites per tetramer.
Hester
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Department of Biochemistry, Virginia Commonwealth University, Richmond 23298, USA.
Kaku
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Goldstein
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Wright
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D000595:Amino Acid Sequence; D001665:Binding Sites / Q000502:physiology; D002413:Cations, Divalent; D027801:Galanthus; D037102:Lectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D037241:Mannose-Binding Lectins; D008766:Methylmannosides / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D013223:Statistics as Topic; D013696:Temperature; D014961:X-Ray Diffraction
D002413:Cations, Divalent; D037102:Lectins; D037241:Mannose-Binding Lectins; D008766:Methylmannosides; D037121:Plant Lectins; D010940:Plant Proteins; C063117:snowdrop lectin; C008466:methylmannoside; D008358:Mannose