title: Small-angle X-ray scattering and crystallographic studies of arcelin-1: an insecticidal lectin-like glycoprotein from Phaseolus vulgaris L.
abstract: Arcelin-1 and alpha-amylase inhibitor are two lectin-like glycoproteins expressed in the seeds of the kidney bean (Phaseolus vulgaris). They display insecticidal activities and protect the seeds from predation by larvae of various bruchids through different biological actions. Solution-state investigations by small-angle X-ray scattering (SAXS) show the dimeric structure of arcelin-1, a requirement for its hemagglutinating properties. Anions were found to have specific properties in their effectiveness to disrupt protein aggregates, affect solubility, and improve crystallizability. The SAXS results were used to improve crystallization conditions, and single crystals diffracting beyond 1.9 A resolution were obtained. X-ray diffraction data analysis shows that noncrystallographic symmetry-related arcelin-1 molecules form a lectin-like dimer and reveals the presence of a solvent-exposed anion binding site on the protein, at a crystal-packing interface. The solution state properties of arcelin-1 and crystal twinning may be explained by the anion specificity of this binding site.
authors.affiliation: Groupe de Cristallographie Biologique, Institut de Pharmacologie et de Biologie Structurale, UPR 9062 CNRS, Toulouse, France.
authors.forename: L
authors.initials: L
authors.lastname: Mourey
authors.forename: J D
authors.initials: JD
authors.lastname: Pédelacq
authors.forename: C
authors.initials: C
authors.lastname: Fabre
authors.forename: H
authors.initials: H
authors.lastname: Causse
authors.forename: P
authors.initials: P
authors.lastname: Rougé
authors.forename: J P
authors.initials: JP
authors.lastname: Samama
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods; D007887:Fabaceae; D006023:Glycoproteins / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry*; D010946:Plants, Medicinal
chemical_list: D006023:Glycoproteins; D007306:Insecticides; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C110154:arcelin-1