Spectroscopy of 2-aminopurine: An MCSCF Study

• Authors: E. Rachofsky , J. Ross , M. Krauss , R. Osman
• Languages of publication: EN

Abstracts

EN

2-aminopurine is a highly fluorescent isomer of adenine that can be incorporated into DNA as a probe of structure, dynamics, and protein-DNA interactions. Interpretation of the fluorescence of 2-aminopurine in DNA requires a model of the electronic structure of this fluorophore in its ground and excited states. To this end, electronic structures and energies of the ground and lowest singlet excited states of 2-amino-9-methylpurine were calculated by the multiconfiguration self-consistent field method supplemented by multiconfiguration perturbation theory. The molecular geometry was optimized in both of these electronic states to permit investigation of both electronic excitation and fluorescence emission. The predicted energies and transition dipoles were in good agreement with experiment. The permanent molecular dipole of 2-amino-9-methylpurine increased upon excitation, suggesting that both the absorption and emission spectra should shift to slightly lower energies in polar solvents. The anomalous spectral shifts observed in water suggest that 2-aminopurine undergoes hydrogen bonding that better stabilizes the ground state than the excited state. From the calculated electrostatic potentials of these two states, the position at which this hydrogen bond forms was predicted. These results form a basis for understanding the excited states and possible intermolecular interactions of 2-aminopurine in DNA.

Keywords

EN

31.15.Ar; 31.50.+w; 33.20.Lg; 33.50.Dq

Discipline

• 33.20.Lg: Ultraviolet spectra
• 33.50.Dq: Fluorescence and phosphorescence spectra

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1998
• Volume: 94
• Issue: 5-6
• Pages: 735-748

Dates

published

1998-11

received

1998-07-23

Contributors

author

E. Rachofsky

• Department of Biochemistry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York NY 10029, USA

author

J. Ross

• Department of Biochemistry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York NY 10029, USA

author

M. Krauss

• Center for Advanced Research in Biotechnology, National Institute of Standards and Technology, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA

author

R. Osman

• Department of Physiology and Biophysics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York NY 10029, USA

Identifiers

DOI

10.12693/APhysPolA.94.735