[Internal symmetry of the mirror type in the primary structure of ribozymes]

Internal symmetry of the mirror type has been first found in molecules of RNA referred to as ribozymes. For identification and investigation of the internal symmetry in RNA primary structure, two methods were developed, dot matrix and scanning, respectively. The methods are based on a comparison of normal and reversible nucleotide sequences. The objects of our study was ribozymes from introns of Tetrahymena thermophila and hepatitis delta virus, and also a group of related ribozymes, possessing both cleavage and ligation activities. The centers of internal symmetry are mainly localized in the catalytic sites and other important regions of ribozyme molecules. A positive correlation was found between the conservativity and symmetry of the primary structure of ribozymes. However, this correlation was not so clear in comparison with the correlation in the case of proteins. As reported earlier (Shpakov, 1995, 2001), the internal symmetry was discovered in protein and DNA molecules. The obtained data enable us to consider the internal symmetry as a common characteristics of nucleotide and amino acid sequences of the biopolymers.