Quantum-chemical analysis of C-H...O and C-H...N interactions in RNA base pairs--H-bond versus anti-H-bond pattern.
Geometries and interaction energies of unusual UU and AA base pairs with one standard hydrogen bond (H-bond) and additional C-H...O or C-H...N contacts have been determined by quantum-chemical methods taking into account electron correlation. Whereas the C-H bond length in the UU C-H...O contact increases upon complex formation (H-bond pattern), the C-H bond of the AA C-H....N interaction is shortened (anti-H-bond pattern). The same properties are found for model complexes between U or A and formaldehyde that have intermolecular C-H...acceptor contacts but no standard H-bonds. Both the C-H...acceptor H-bond and anti-H-bond interactions are attractive. A possible influence of the donor CH group charge distribution on the interaction pattern is discussed.
Biocomputing, Institut für Molekulare Biotechnologie, Jena, Germany.
M
M
Brandl
M
M
Meyer
J
J
Sühnel
D000225:Adenine / Q000737:chemistry; D020029:Base Pairing; D002244:Carbon / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D005557:Formaldehyde / Q000737:chemistry; D006860:Hydrogen Bonding; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D011789:Quantum Theory; D012313:RNA / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry
D005557:Formaldehyde; D014498:Uracil; D012313:RNA; D002244:Carbon; D000225:Adenine; D009584:Nitrogen; D010100:Oxygen