Characterization of calcium binding to brain spectrin.Show full item record
|Title||Characterization of calcium binding to brain spectrin.|
|Author||Wallis, C. J.; Wenegieme, Elizabeth F.; Babitch, Joseph A.|
|Abstract||Brain spectrin alpha and beta chains bind 45Ca2+, as shown by the calcium overlay method. Flow dialysis measurements revealed eight high affinity binding sites/tetramer that comprise two binding components (determined by nonlinear regression analysis). The first component has one or two sites (kd = 2-30 x 10(-8) M), depending on the ionic strength of the binding buffer, with the remaining high affinity sites in the second component (kd = 1-3 x 10(-6) M). In addition, there is a variable, low affinity binding component (n = 100-400, kd = 1-2 x 10(-4) M). Magnesium inhibits calcium binding to the low affinity sites with a K1 = 1.21 mM. Proteolytic fragments from trypsin or chymotrypsin digests of brain spectrin bind 45Ca2+ if they include alpha domain IV, alpha domain III, or the amino-terminal half of the beta chain (but more than 25 kDa from the amino-terminal). These data suggest that calcium ions bind with high affinity to the putative EF-hands in alpha domain IV and to one site in the amino-terminal half of the beta chain that is associated with alpha domain IV in the native dimer. The localization is consistent with a direct calcium modulation of the spectrin-actin-protein 4.1 interaction. In addition, there appears to be one high affinity site near the hypersensitive region of alpha brain spectrin. All four proposed binding sites occur near probable calmodulin-binding or calcium-dependent protease cleavage sites.|
|Department||Chemistry and Biochemistry|
Electrophoresis, Polyacrylamide Gel
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- Research Publications 
Showing a few items related by title, author, creator and subject.
Anthony, Francis Andrew (1984)A method was improved to detect ('45)Ca('2+)-binding proteins in polyacrylamide gels. It was shorter, quantitative, highly reproducible, and resulted in a 40-fold enhanced sensitivity over the previous method. The technique ...
Thompson, Tina Louise (1986)Chick forebrain synaptosomes were incubated with inorganic phosphate (('32)Pi) under conditions which result in the labeling of only internal components. The synaptosomes were rapidly subfractionated into synaptic plasma ...
Kong, Chuang Fong (1988)Some cytoskeletal proteins have been found to bind calcium (Anthony and Babitch, 1984). We investigated the calcium binding properties of brain tubulin, erythrocyte and brain spectrins, and muscle and platelet tropomyosins. ...