Structural aspects of catalytic mechanisms of endonucleases and their binding to nucleic acids

Abstract

Endonucleases (EC 3.1) are enzymes of the hydrolase class that catalyze the hydrolytic cleavage of deoxyribonucleic and ribonucleic acids at any region of the polynucleotide chain. Endonucleases are widely used both in biotechnological processes and in veterinary medicine as antiviral agents. Medical appli cations of endonucleases in human cancer therapy hold promise. The results of X ray diffraction studies of the spatial organization of endonucleases and their complexes and the mechanism of their action are ana lyzed and generalized. An analysis of the structural studies of this class of enzymes showed that the specific binding of enzymes to nucleic acids is characterized by interactions with nitrogen bases and the nucleotide backbone, whereas the nonspecific binding of enzymes is generally characterized by interactions only with the nucleic acid backbone. It should be taken into account that the specificity can be modulated by metal ions and certain low molecular weight organic compounds. To test the hypotheses about specific and non specific nucleic acid binding proteins, it is necessary to perform additional studies of atomic resolution three dimensional structures of enzyme-nucleic acid complexes by methods of structural biology.