Nucleotide recognition by protonated aminoglycosides

摘要: Interactions of protonated forms kanamycin A with nucleotides and several simple phosphate anions have been studied by potentiometric NMR titrations. The affinity to is comparable that observed other aliphatic polyammonium receptors similar charge, but it discriminates triphosphate different nucleobases binding constants following the order GTP≫CTP ≈ ATP. Kanamycin also binds respective uncharged nucleosides same selectivity. Binding ATP exothermic a negative entropic contribution in contrast what expected for ion pairing. Other tested aminoglycosides, amikacin streptomycin, bind less efficiently than A. Models structures complexes GTP obtained molecular mechanics (OPLS-2005) calculations based on 1H 31P data confirm possibility nucleotide discrimination simultaneous pairing terminal groups ammonium sites...