IMPORTANT ROLE OF WEAK-INTERACTIONS IN LONG DNA AND RNA MOLECULE RECOGNITION BY ENZYMES (A REVIEW)

In general, small ligand recognition by enzymes is based on formation of several strong contacts like hydrogen bonds, electrostatic contacts , or stacking interactions with specific structural elements or single nucleotide links of specific sequences, so that only selected nucleot ide links are involved in the extended RNA and DNA complexes with <<si te-specific>> enzymes. As a rule, weak electrostatic, hydrophobic, and van der Waals interactions do not play any significant role in the sm all ligand or single-nucleotide recognition by enzymes. However, some enzymes involved in the nucleic acid transformation interact with all nucleotides accessible. For the 10-30-link-long substrates the contrib ution of weak interactions to the substrate affinity may be close to 4 -7 orders of magnitude and predominate over the stronger ones owing to the additivity of free energies of individual link recognition. New m ethods of studying weak interactions are analyzed in the review, tryin g to prove that weak interactions of nucleic acids are especially impo rtant for the specificity of their recognition and transformation (as shown for the most important enzymes involved in replication and repai r).