title: Two-dimensional crystallization on lipid monolayers and three-dimensional structure of sticholysin II, a cytolysin from the sea anemone Stichodactyla helianthus.
abstract: Sticholysin II (Stn II), a potent cytolytic protein isolated from the sea anemone Stichodactyla helianthus, has been crystallized on lipid monolayers. With Fourier-based methods, a three-dimensional (3D) model of Stn II, up to a resolution of 15 A, has been determined. The two-sided plane group is p22(1)2, with dimensions a = 98 A, b = 196 A. The 3D model of Stn II displays a Y-shaped structure, slightly flattened, with a small curvature along its longest dimension (51 A). This protein, with a molecular mass of 19. 2 kDa, is one of the smallest structures reconstructed with this methodology. Two-dimensional (2D) crystals of Stn II on phosphatidylcholine monolayers present a unit cell with two tetrameric motifs, with the monomers in two different orientations: one with its longest dimension lying on the crystal plane and the other with this same axis leaning at an angle of approximately 60 degrees with the crystal plane.
authors.affiliation: Centro de Microscopía Electrónica "Luis Brú," Universidad Complutense, 28040 Madrid, Spain. jmartinb@cub.uam.es
authors.forename: J
authors.initials: J
authors.lastname: Martín-Benito
authors.forename: F
authors.initials: F
authors.lastname: Gavilanes
authors.forename: V
authors.initials: V
authors.lastname: de Los Ríos
authors.forename: J M
authors.initials: JM
authors.lastname: Mancheño
authors.forename: J J
authors.initials: JJ
authors.lastname: Fernández
authors.forename: J G
authors.initials: JG
authors.lastname: Gavilanes
mesh_terms: D000818:Animals; D002784:Cholesterol; D003064:Cnidarian Venoms / Q000737:chemistry*; D003460:Crystallization; D005583:Fourier Analysis; D006460:Hemolysin Proteins / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D008081:Liposomes; D008854:Microscopy, Electron; D008958:Models, Molecular; D010713:Phosphatidylcholines; D012615:Sea Anemones; D012984:Software; D013109:Sphingomyelins
chemical_list: D003064:Cnidarian Venoms; D006460:Hemolysin Proteins; D008081:Liposomes; D010713:Phosphatidylcholines; D013109:Sphingomyelins; C404794:sticholysin II; D002784:Cholesterol