title: Hydrodynamic properties of human adhesion/growth-regulatory galectins studied by fluorescence correlation spectroscopy.
abstract: Fluorescence correlation spectroscopy is applied on homologous human lectins (i.e., adhesion/growth-regulatory galectins) to detect influence of ligand binding and presence of the linker peptide in tandem-repeat-type proteins on hydrodynamic properties. Among five tested proteins, lactose binding increased the diffusion constant only in the cases of homodimeric galectin-1 and the linkerless variant of tandem-repeat-type galectin-4. To our knowledge, the close structural similarity among galectins does not translate into identical response to ligand binding. Kinetic measurements show association and dissociation rate constants in the order of 1 to 10(3) M(-1) s(-1) and 10(-4) s(-1), respectively. Presence of the linker peptide in tandem-repeat-type protein leads to anomalous scaling with molecular mass. These results provide what we believe to be new insights into lectin responses to glycan binding, detectable so far only by small angle neutron scattering, and the structural relevance of the linker peptide. Methodologically, fluorescence correlation spectroscopy is shown to be a rather simple technical tool to characterize hydrodynamic properties of these proteins at a high level of sensitivity.
authors.affiliation: Applied Laser Physics and Laser Spectroscopy, Bielefeld University, Bielefeld, Germany.
authors.forename: Antonia
authors.initials: A
authors.lastname: Göhler
authors.forename: Sabine
authors.initials: S
authors.lastname: André
authors.forename: Herbert
authors.initials: H
authors.lastname: Kaltner
authors.forename: Markus
authors.initials: M
authors.lastname: Sauer
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Gabius
authors.forename: Sören
authors.initials: S
authors.lastname: Doose
mesh_terms: D000818:Animals; D004058:Diffusion; D037161:Galectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D007785:Lactose / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D008970:Molecular Weight; D033363:Neutron Diffraction; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D053838:Scattering, Small Angle; D017384:Sequence Deletion; D013050:Spectrometry, Fluorescence / Q000379:methods*; D020080:Tandem Repeat Sequences / Q000235:genetics
chemical_list: D037161:Galectins; D008024:Ligands; D007785:Lactose