Thursday, November 15, 2012

GDP and SRL don't mix

Translational GTPases run the ribosomal cycle, and the ribosome talks back - it recruits the GTPases when it is a certain state, affects trGTPase's affinity to G nucleotides and activates the GTP hydrolysis when needed. Using Isothermal Titration Calorimetry we showed that binding of GDP nucleotide and of SRL rRNA element to translational GTPases IF2 and EF-G are mutually exclusive. This suggests a neat mechanism for the destabilisation of the ribosome-bound GDP form of the GTPase: the moor has done his duty, the moor can go.

Due to the technical limitations, the ITC experiments were performed with a 27-nucleotide long RNA piece mimicking the rRNA element as a model. In order to place our results in the framework of the ribosomal cycle we need experiments with the whole ribosome. 

References:

Mitkevich et al., Scientific Reports 2012 2:843, PIMD: 32150791

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