Adenine/thymine base pair

Sobolewski AL, Domcke W (2006) Role of electron-driven proton-transfer processes in the excited-state deactivation adenine-thymine base pair. J Phys Chem A 110 9031-9038... 

Nowick JS, Chen JS. Molecular recognition in aqueous micellar solution—adenine thymine base-pairing in SDS micelles. J Am Chem Soc 1992 114 1107-1108. 

The energies of the molecular orbitals of the adenine-thymine base pair have been calculated by several authors to elucidate the effect of hydrogen bond formation on the properties of the bases (for u-HMO calculations, see refs. 1, 140, 171, 263). 

Reynisson J, Steenken S (2002b) DFT studies on the base pairing abilities of the one-electron reduced or oxidizes adenine-thymine base pair. Phys Chem Chem Phys 4 5353-5358... 

Fig. 2 Schematic representations of two model duplexes composed of homopolymeric and alternating adenine-thymine base-pairs for clarity adenines are shown in green.

The BFPT process may take place whenever an excess electron is attached to a nucleobase interacting with a proton donor. In particular, the role of a proton donor could be filled by another nucleobase. Especially interesting are complementary base pairs, AT and GC, since these systems appear in DNA. In the case of the adenine-thymine base pair (AT), a combination of three proton donor and acceptor pairs of adenine with three proton donor and acceptor pairs of thymine leads to nine possible, planar, cyclic H-bonded complexes (see Figure 21-22 [49]). 

Kabelac, M. Zendlova, L. Reha, D. Hobza, P. Potential energy surfaces of an adenine-thymine base pair and its methylated analogue in the presence of one and two water molecules Molecular mechanics and correlated ab initio study, J. Phys. Chem. B 2005,109, 12206-12213. 

Hrouda, V., Florian, J., and Hobza, R, Structure, energetics and harmonic vibrational spectra of the adenine-thymine and adenine -thymine base pairs Gradient nonempirical and semi-empirical study, J. Phys. Chem. 97, 1542-1557 (1993). 

Gould, I. R. and Kollman, P. A., Theoretical investigation of the hydrogen bond strengths in guanine-cytosine and adenine-thymine base pairs, J. Am. Chem. Soc. 116, 2493-2499 (1994). 

Considerable attention has also been devoted by several investigators to the theoretical study of the potential curves for hydrogen bonds of the guanine-cytosine and adenine-thymine base pairs. An accurate representation of this potential is important because the genetic code is contained in this interaction. Lowdin has suggested that mutations may be a result of a shift in position of the hydrogen bond protons in the base units of DNA via proton tunneling. " The idea of proton... 

OCHg, SH, NHg, CHg, or COOH, ° adenine-thymine base pair - and its cationic and anionic forms (for the charge densities at C-5 and C-6 positions in uracil, thymine, 5-amino- 5-nitro- and 6-methyl-uracil, 6-azathymine and orotic acid, see refs. 187, 188) tt-HMO - -a-Del Re calculations on uracil, - 5-fluoro- and 5-bromouracil, 5,6-dihydrouracil and its anionic form tt-SCF MO -f a-Del Re... 

Dipole moment of the adenine-thymine base pair has also been calculated. 

The flexible porphyrin-anthracene system of Sirish and Maiya assembles via complementary adenine-thymine base pairing [115]. Ensemble 30 associates with a binding constant of /Ca = 47 + 5 M. H NMR data suggest that both Hoogsteen and Watson-Crick adenine-thymine associations exist in solution. Time-resolved fluorescence data are consistent with the possibility of energy and electron transfer from the singlet excited state of the anthracene to the porphyrin. 

Yet another effect of the action of Ag" has been described, namely, its interaction with nucleic acids [112]. The Ag" ion interacts preferentially with the bases found in DNA rather than with the phosphate group [113-118]. The reaction between Ag and a GC (guanine-cytosine) base pair proceeds via two steps, whereas that between Ag" and an AT (adenine-thymine) base pair requires only one step [116], Ag appears to be attached to the N atom... 

Figure 34 From left to right initial, transition, and final state for the double proton transfer process in an adenine-thymine base pair. Reproduced with permission of American Institute of Physics from 133...

Kumar, C. V., Punzalan, E. H. A. and Tan, W. B. (2000) Adenine-thymine base pair recognition by an anthryl probe from the DNA minor groove. Tetrahedron, 56, 7027-7040. 

Kopka et al. (186) solved the X-ray crystal structure of netropsin (1) complexed with CGCGAATTBrCGCG at 2.2 A resolution. Netropsin binds to the minor groove of double helical B-DNA and is selective for four or more A-T (adenine-thymine) base pairs a single G-C (guanosine-cytosine) pair prevents binding (see color insert, Figure 10). Netropsin s amide NH groups... 

How many hydrogen bonds link the adenine-thymine base pair ... 

D Molecules Adenine-thymine base pair Guanine-[Pg.1121]

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