Bound to switch proteins, the GTP molecule is vital for the deactivation of many of them. If one of the three phosphate groups is detached from GTP, the protein switches to "off," thus affecting cellular processes. "The proteins are extremely efficient and accelerate reactions that would usually take billions of years so that they are executed within the fraction of a second," says Klaus Gerwert.
At least one water molecule is always involved in the deactivation process. To date, researchers assumed that this water molecule had to be activated -- namely by a reaction partner transferring a proton to the water molecule. "The nature of the reaction partner has been argued for decades -- is it the GTP itself or is it a protein component," explains Carsten Kötting, one of the authors from the Bochum-based team. "In the current study, we have surprisingly identified an entirely new mechanism, where the activation takes place without any proton transfer whatsoever."
Analysis - Team - Deactivation - Options - Switch
Using computer-aided analysis, the team studied all deactivation options for seven different switch protein systems. The researchers thus identified various speeds for the deactivation process....
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