(Satellite tobacco ringspot virus) and CchMVd (Chrysanthemum Chlorotic Mottle Viroid) ribozymes and of the ADHR1 et ADHR2 mutants
Within the context of the RNA world, the study of the catalytic activity of a ribozyme under pressure makes it possible to examine the behavior of this molecule under extreme conditions. Today, many organisms are faced with such extreme conditions, but the mechanims and the behavior of these macromolecules are poorly understood. Our results on the wild ribozymes of sTRSV and CChMVd and on the mutants ADHR1 abd ADHR2 confirm the results obtained from cristallographic pictures and highlight the folding and plasticity of the RNA molecule. In addition, they provide informations on the amplitude of these dynamics (Tobé et al, 2005 ; Hervé et al, 2006, Buck et al, 2009 ; Ztouti et al, 2009 ; Kaddour et al, 2011 ; Kaddour et al, 2014). The activity, auto-association and the structure of the ribozymes ADHR1 and AHDR2 were studied by analytical centrifugation and neutron scattering. Stem-stem, loop-loop and stem-loop interactions play a major role in the regulation of the two ribozymes (Li et al, 2008). We followed the conformational changes of the pre- and post-catalytic states of ADHR1. Interaction of the RNA with adenine is transient, the dynamics induced constitutes the limiting step of the catalysis (Buck et al, 2009).