A novel magnesium‐dependent mechanism for the activation of transducin by fluoride
- 30 July 1990
- journal article
- Published by Wiley in FEBS Letters
- Vol. 268 (1) , 277-280
- https://doi.org/10.1016/0014-5793(90)81027-l
Abstract
Activation of transducin‐GDP by NaF is mainly mediated by aluminofluoride or beryllofluoride complexes acting as GTP γ‐phosphate analogs. In millimolar magnesium, NaF at concentrations above 3 mM is active even in the absence of aluminium or beryllium. This activation has a Hill coefficient of 3 with respect to F−, and its rate is linear with respect to Mg2+ concentrations above 2 mM. Upon fluoride dilution, inactivation rate is hundreds of times faster than for aluminofluoride‐activated TαGDP. We propose that at high NaF concentrations, 3 hydrogen‐bonded fluorides in the γ‐phosphate site of TαGDP entrap a magnesium counterion and this induces the transconformation to the TαGTP form.Keywords
This publication has 11 references indexed in Scilit:
- Aluminofluoride and beryllofluoride complexes: new phosphate analogs in enzymologyTrends in Biochemical Sciences, 1990
- The intrinsic fluorescence of the alpha subunit of transducin. Measurement of receptor-dependent guanine nucleotide exchange.Journal of Biological Chemistry, 1988
- Ternary hydroxide complexes in neutral solutions of A13+ and F−Biochemical and Biophysical Research Communications, 1988
- Effects of Mg2+ and the beta gamma-subunit complex on the interactions of guanine nucleotides with G proteins.Journal of Biological Chemistry, 1987
- The effect of GTP and Mg2+ on the GTPase activity and the fluorescent properties of Go.Journal of Biological Chemistry, 1987
- The effect of activating ligands on the intrinsic fluorescence of guanine nucleotide-binding regulatory proteins.Journal of Biological Chemistry, 1987
- Fluoroaluminates activate transducin‐GDP by mimicking the γ‐phosphate of GTP in its binding siteFEBS Letters, 1985
- Guanine nucleotides and magnesium dependence of the association states of the subunits of transducinFEBS Letters, 1984
- Aluminum: a requirement for activation of the regulatory component of adenylate cyclase by fluoride.Proceedings of the National Academy of Sciences, 1982