title: Preliminary crystallographic characterization of ricin agglutinin.
abstract: The quaternary structure of ricin agglutinin (RCA) has been determined by x-ray crystallography. The refined structure of ricin proved to be a successful search model using the molecular replacement method of phase determination. RCA forms an elongated molecule of dimensions 120 A x 60 A x 40 A with two A chains at the center and a B chain at each end. The A chains are covalently associated via a disulfide bridge between Cys 156 of both chains. Additional contacts at residues 114-5 stabilize the dimer interface. The covalent association of RCAA chains was confirmed by gel filtration under reducing and nonreducing conditions.
authors.affiliation: Department of Crystallography, Birkbeck College, University of London, United Kingdom.
authors.forename: E C
authors.initials: EC
authors.lastname: Sweeney
authors.forename: A G
authors.initials: AG
authors.lastname: Tonevitsky
authors.forename: D E
authors.initials: DE
authors.lastname: Temiakov
authors.forename: I I
authors.initials: II
authors.lastname: Agapov
authors.forename: S
authors.initials: S
authors.lastname: Saward
authors.forename: R A
authors.initials: RA
authors.lastname: Palmer
mesh_terms: D018360:Crystallography, X-Ray; D037102:Lectins / Q000737:chemistry*; D008958:Models, Molecular; D037121:Plant Lectins; D011487:Protein Conformation
chemical_list: D037102:Lectins; D037121:Plant Lectins; C017707:Ricinus communis agglutinin-1