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MECHANISM OF INTERACTION OF MYELIN BASIC PROTEIN AND S‐100 PROTEIN: METAL BINDING AND FLUORESCENCE STUDIES 1, 2
Author(s) -
Perumal A. S.,
Mahadik S. P.,
Rapport M. M.
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb01560.x
Subject(s) - chemistry , conformational change , fluorescence , binding protein , biophysics , myelin basic protein , binding site , crystallography , biochemistry , biology , myelin , physics , quantum mechanics , neuroscience , gene , central nervous system
— It has been reported that myelin basic protein (MBP) forms a specific complex with S‐100 protein in the presence of either Ca 2+ or Mn 2+ , as detected by Immunoelectrophoresis. We have now studied the binding of Ca 2+ and Mn 2+ to these two proteins. We find that MBP binds 1 mol of Mn 2+ /mol of protein, and this binding produces an increment in its fluorescence, indicating a conformational change. Ca 2+ does not bind to MBP nor does it affect the fluorescence of MBP. S‐100 protein, as has been reported, binds about 10 mol of Ca 2+ /mol and this binding produces a conformational change. S‐100 protein also has 25 binding sites for Mn 2+ , but this binding does not alter fluorescence and does not appear to affect conformation. Competitive binding experiments demonstrate that the binding sites of S‐100 protein for Ca 2+ and Mn 2+ are independent. The alteration of electrophoretic migration in gels of S‐100 protein produced by Ca 2+ and of MBP produced by Mn 2+ are in accord with the observations based on fluorescence. Mn 2+ does not affect the electrophoretic mobility of S‐100. These results indicate that the formation of the complex between MBP and S‐100 protein in the presence of either Ca 2+ or Mn 2+ is due to the conformational change induced by these ions in S‐100 protein, MBP, or both.