Experimental results from host-guest complexes for the design of effectors in biological systems and of enzyme analogous catalysts.
Strategies and results for the extraction of biologically important non-covalent binding increments from studies of synthetic host-guest complexes are described with selected examples. Systematic analyses of association constants and the corresponding complex conformation in solution allows us to assign specific values to different pairwise interactions, including salt bridges, amide-type hydrogen bonds, van der Waals effects, and metal ion interactions. A comparison of association constants between selected flexible and rigid ion pairs shows few differences, indicating that different entropy contributions either are small, or cancel with corresponding enthalpy changes, at least in weakly bound complexes. The supramolecular design of enzyme-analogous catalysts is illustrated with complexes containing, e.g. strongly bound yet still active Ln3+ ions, e.g. in an azacrown ether, and groups which support association with nucleic acids and can serve as nucleophiles. The experimentally observed hydrolysis rate enhancements with such artificial nucleases amount to 10(6) and more, both with phenyl phosphates and with ds-DNA.
Schneider
H J
HJ
FR Organische Chemie, Universität des Saarlandes, Saarbrücken, Germany.
Eblinger
F
F
Sartorius
J
J
Rammo
J
J
D004247:DNA / Q000737:chemistry / Q000378:metabolism; D003851:Deoxyribonucleases / Q000737:chemistry / Q000378:metabolism; D015195:Drug Design; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D007477:Ions; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011073:Polyamines / Q000737:chemistry / Q000378:metabolism; D019287:Zinc Sulfate / Q000737:chemistry / Q000378:metabolism
D004798:Enzymes; D007477:Ions; D011073:Polyamines; D019287:Zinc Sulfate; D004247:DNA; D003851:Deoxyribonucleases