A novel magnesium‐dependent mechanism for the activation of transducin by fluoride
Authors:
- Bruno AntonnyBABruno Antonny
- Joelle BigayJBJoelle Bigay
- Marc ChabreMCMarc Chabre
- 30 July 1990
- journal article
- Published by Wiley in FEBS Letters
- Vol. 268 (1) , 277-280
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
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