[The structural changes in the ribosome during the elongation cycle]

The plenty of data about structural changes in the ribosome during its functioning has been accumulated. The most interesting information on such changes was obtained by cryo-EM of various ribosomal complexes with the ligands and by combination of rRNA site-directed mutagenesis with the analysis of structural changes in ribosome by chemical modification technique (chemical probing). The most studied structural transformations of the ribosome interacting with tRNAs and elongation factors are considered in this review. The structural rearrangements are discussed in the context of interactions between the functional centers of the ribosome. We also describe the system of tertiary contacts between the rRNA helices and proteins which forms the universal structure in the ribosome. We pay attention that by means of such system the allosteric conformational signal can be transmitted between the functional centers. Besides the discussion of different biochemical data in the scope of structural data we also consider the hypothesis that the position of GTPase associated center (GAC) in the ribosome regulates the binding of elongation factors.