title: Crystal structure of tandem type III fibronectin domains from Drosophila neuroglian at 2.0 A.
abstract: We report the crystal structure of two adjacent fibronectin type III repeats from the Drosophila neural cell adhesion molecule neuroglian. Each domain consists of two antiparallel beta sheets and is folded topologically identically to single fibronectin type III domains from the extracellular matrix proteins tenascin and fibronectin. beta bulges and left-handed polyproline II helices disrupt the regular beta sheet structure of both neuroglian domains. The hydrophobic interdomain interface includes a metal-binding site, presumably involved in stabilizing the relative orientation between domains and predicted by sequence comparision to be present in the vertebrate homolog molecule L1. The neuroglian domains are related by a near perfect 2-fold screw axis along the longest molecular dimension. Using this relationship, a model for arrays of tandem fibronectin type III repeats in neuroglian and other molecules is proposed.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125.
authors.forename: A H
authors.initials: AH
authors.lastname: Huber
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
authors.forename: A J
authors.initials: AJ
authors.lastname: Bieber
authors.forename: P J
authors.initials: PJ
authors.lastname: Bjorkman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry; D003460:Crystallization; D018360:Crystallography, X-Ray; D004330:Drosophila / Q000737:chemistry*; D010450:Endopeptidases / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D005353:Fibronectins / Q000737:chemistry* / Q000235:genetics; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009457:Neuroglia / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D017433:Protein Structure, Secondary; D012091:Repetitive Sequences, Nucleic Acid; D019063:Tenascin
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D008670:Metals; D010446:Peptide Fragments; D019063:Tenascin; D010450:Endopeptidases