title: Quantitative assessment of the association of the alpha-I fragment of spectrin with oligomers of intact spectrin.
abstract: The alpha-I fragment of human spectrin that carries the binding site on the alpha-chain of spectrin for the beta-chain has been purified from limited trypsin digests of spectrin by means of FPLC. The self-association of spectrin and the binding of the alpha-I fragment to spectrin heterodimers and to tetramers have been quantified through the use of gel electrophoresis, staining with Coomassie Blue, and quantification of the bound dye following elution with pyridine. The parameters of self-association were found to be consistent with those estimated from sedimentation equilibrium analysis. The data were consistent with a model in which both self-association and the binding of the alpha-I fragment are considered to occur through an intermediate in which the alpha-beta interface is initially dissociated. The alpha-beta interface in the heterodimer was found to be less stable than that of higher oligomers by approx. 3 kJ/mol.
authors.affiliation: Department of Biochemistry, University of Sydney, NSW, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Cole
authors.forename: G B
authors.initials: GB
authors.lastname: Ralston
mesh_terms: D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers; D013049:Spectrin / Q000737:chemistry / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D011108:Polymers; D013049:Spectrin; D014357:Trypsin