Magnesium-induced structural changes in tubulin.
Exogenously added Mg2+, in the intracellular concentration range, has significant effect on the conformation of tubulin as monitored by tryptophan fluorescence. This magnesium-induced conformational change is reflected in the change of the slope and intercept of the Lehrer plot. The off-rate of colchicine from colchicine-tubulin complex is also decreased severalfold upon the addition of exogenous magnesium. The conformational change is magnesium-specific, and magnesium can only be replaced by manganese. GTP, CaCl2, and NaCl have no effect. Magnesium, however has no effect on tryptophan accessibilities of tubulin-S. Implications of these results are discussed in terms of C-terminal tail-body interaction.
Department of Biophysics, Bose Institute, Calcutta, India.
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Bhattacharya
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Bhattacharyya
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Roy
D000818:Animals; D001665:Binding Sites; D005453:Fluorescence; D006041:Goats; D008274:Magnesium / Q000737:chemistry*; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D009711:Nucleotides / Q000378:metabolism; D011487:Protein Conformation; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure
D009711:Nucleotides; D014404:Tubulin; D008274:Magnesium