A THEORETICAL-STUDY OF THE CYTOSINE EXCIMER STATE - THE ROLE OF GEOMETRY OPTIMIZATION

被引:18
作者
DANILOV, VI
SLYUSARCHUK, ON
ALDERFER, JL
STEWART, JJP
CALLIS, PR
机构
[1] MONTANA STATE UNIV,DEPT CHEM,BOZEMAN,MT 59717
[2] ROSWELL PK CANC INST,DEPT BIOPHYS,BUFFALO,NY 14263
[3] STEWART COMPUTAT CHEM,COLORADO SPRINGS,CO 80921
[4] UKRAINIAN ACAD SCI,INST MOLEC BIOL & GENET,DEPT QUANTUM BIOPHYS,KIEV 252143,UKRAINE
关键词
D O I
10.1111/j.1751-1097.1994.tb05010.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
A study of the lowest excited dimer (excimer) singlet state of the DNA base cytosine was performed with fully optimized geometry (near the cis-syn form) using a slightly modified version of MOPAC6 (AM1 hamiltonian) and 112 excited configurations involving an active space consisting of the four highest occupied and the two lowest empty MO of the dimer. A binding energy of 3 kcal/mol for the excimer state is demonstrated, and the excimer fluorescence is predicted to be shifted 150 nm to longer wavelengths relative to that of the monomer fluorescence. The excimer geometry has the planes nonparallel (40-45 degrees interplanar angle) and distorted, with the C-5-C-6 showing quite close contact (2.4 Angstrom). Excitation is found to be more localized in the region of the C-5-C-6 bond than expected from the monomer wavefunction. No stable excimer was found if the planes were constrained to be planar, nor if the triplet state was selected. The results suggest that the excimer geometry found in this study may be a precursor to the cis-syn cyclobutane photodimer.
引用
收藏
页码:125 / 129
页数:5
相关论文
共 38 条
[21]   LUMINESCENCE OF DINUCLEOTIDES AT 77 DEGREES K [J].
IMAKUBO, K .
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 1968, 24 (05) :1124-&
[22]  
KLEINWAECHTER V, 1972, Studia Biophysica, V33, P1
[23]   SEMIEMPIRICAL VALENCE-ELECTRON CALCULATIONS OF EXCITED-STATE GEOMETRIES AND VIBRATIONAL FREQUENCIES [J].
KLESSINGER, M ;
POTTER, T ;
VONWULLEN, C .
THEORETICA CHIMICA ACTA, 1991, 80 (01) :1-17
[24]   EXCITED STATE PRECURSORS OF THYMINE PHOTODIMERS [J].
LAMOLA, AA .
PHOTOCHEMISTRY AND PHOTOBIOLOGY, 1968, 7 (06) :619-&
[25]   PHOTODIMERIZATION AND VANDERWAALS STACKING OF DIMETHYLTHYMINE IN WATER [J].
LISEWSKI, R ;
WIERZCHO.KL .
JOURNAL OF THE CHEMICAL SOCIETY D-CHEMICAL COMMUNICATIONS, 1969, (07) :348-&
[26]   INTERACTIONS BETWEEN CYTIDINE AND ITS CATION IN POLYCYTIDYLIC ACID, CYTIDYLYL-3'-CYTIDINE, AND CYTIDINE AGGREGATES [J].
MONTENAY.T ;
HELENE, C .
BIOCHEMISTRY, 1970, 9 (14) :2865-&
[27]   EXCITED-STATES OF DNA AND ITS COMPONENTS AT ROOM-TEMPERATURE .4. SPECTRAL, POLARIZATION AND QUANTUM YIELD STUDIES OF EMISSIONS FROM CPC AND POLY-RC [J].
MORGAN, JP ;
DANIELS, M .
PHOTOCHEMISTRY AND PHOTOBIOLOGY, 1980, 31 (03) :207-213
[28]   THEORY OF ELECTRONIC SPECTRA OF AROMATIC HYDROCARBON DIMERS [J].
MURRELL, JN ;
TANAKA, J .
MOLECULAR PHYSICS, 1964, 7 (04) :363-&
[29]   SOLUTION PHASE PHOTODIMERIZATION OF TETRAMETHYLURACIL - FURTHER-STUDIES ON PHOTOCHEMISTRY OF GROUND-STATE AGGREGATES [J].
OTTEN, JG ;
YEH, CS ;
BYRN, S ;
MORRISON, H .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1977, 99 (19) :6353-6359
[30]   MNDOC STUDY OF EXCITED-STATES [J].
SCHWEIG, A ;
THIEL, W .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1981, 103 (06) :1425-1431