title: Structure of the calcium-dependent lectin domain from a rat mannose-binding protein determined by MAD phasing.
abstract: Calcium-dependent (C-type) animal lectins participate in many cell surface recognition events mediated by protein-carbohydrate interactions. The C-type lectin family includes cell adhesion molecules, endocytic receptors, and extracellular matrix proteins. Mammalian mannose-binding proteins are C-type lectins that function in antibody-independent host defense against pathogens. The crystal structure of the carbohydrate-recognition domain of a rat mannose-binding protein, determined as the holmium-substituted complex by multiwavelength anomalous dispersion (MAD) phasing, reveals an unusual fold consisting of two distinct regions, one of which contains extensive nonregular secondary structure stabilized by two holmium ions. The structure explains the conservation of 32 residues in all C-type carbohydrate-recognition domains, suggesting that the fold seen here is common to these domains. The strong anomalous scattering observed at the Ho LIII edge demonstrates that traditional heavy atom complexes will be generally amenable to the MAD phasing method.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032.
authors.forename: W I
authors.initials: WI
authors.lastname: Weis
authors.forename: R
authors.initials: R
authors.lastname: Kahn
authors.forename: R
authors.initials: R
authors.lastname: Fourme
authors.forename: K
authors.initials: K
authors.lastname: Drickamer
authors.forename: W A
authors.initials: WA
authors.lastname: Hendrickson
mesh_terms: D000209:Acute-Phase Proteins / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry; D003461:Crystallography; D006695:Holmium; D006860:Hydrogen Bonding; D007811:Lanthanum; D037102:Lectins / Q000737:chemistry*; D008024:Ligands; D037241:Mannose-Binding Lectins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011487:Protein Conformation; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D000209:Acute-Phase Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D037102:Lectins; D008024:Ligands; D037241:Mannose-Binding Lectins; D011994:Recombinant Proteins; D007811:Lanthanum; D003094:Collagen; D002118:Calcium; D006695:Holmium