Cytosine base pairing

Examine AT pair and GC pair, adenine-thymine and guanine-cytosine base pairs, respectively. Identify the hydrogen bonds in each. Are they the same as those you sketched Are the base pairs flat as normally drawn in textbooks, or are they significantly puckered or twisted ... 

Abo-Riziq A, Grace L, Nir E, Kabelac M, Hobza P, de Vries MS (2005) Photochemical selectivity in guanine-cytosine base-pair structures. Proc Natl Acad Sci USA 102 20-23... 

Sobolewski AL, Domcke W, Hattig C (2005) Tautomeric selectivity of the excited-state lifetime of guanine/cytosine base pairs The role of electron-driven proton-transfer processes. Proc Natl Acad Sci USA 102 17903-17906... 

Sobolewski AL, Domcke W (2004) Ab initio studies on the photophysics of the guanine-cytosine base pair. Phys Chem Chem Phys 6 2763... 

These definitions apply to any atomic system, molecule or crystal. Fig. 7.3 a illustrates their application to the charge distribution of the guanine-cytosine base-pair. Fig. 7.3 b shows the molecular structure defined by the bond paths and the associated CPs that clearly and uniquely define the three hydrogen bonds that link the two bases. Fig. 7.3 c shows the atomic boundaries and bond paths overlaid on the electron density in the plane of the nuclei. All properties of the atoms can be determined, enabling one, for example, to determine separately the energy of formation of each of the three hydrogen bonds. 

Guanine-Cytosine Base-Pair Interacting with Metal Cations... 

It is a potent antitumor antibiotic isolated from Streptomyces organism. It binds tightly to double stranded DNA through intercalation between adjacent guanine cytosine base pair and inhibit all forms of DNA dependent RNA synthesis. 

Density of states weighted Franck-Condon factor Deoxyribonucleic acid Barrier height for the adiabatic hole motion Difference in ionization potentials of adenine-thymine and guanine-cytosine base pairs... 

Length of the bridge containing adenine-cytosine base pairs only Lowest unoccupied molecular orbital Marcus reorganization energy Mass of the tunneling particle... 

Up to now, quantum-mechanical methods have not been applied to the study of the vibrational spectra of cytosine (see Section V, however, for an interpretation of the hydrogen bond vibrational spectra of the quanine-cytosine base pair). 

Dipole moment of guanine-cytosine base pair has also been calculated. h Hybridization moment. 

Hutter M, Clark T (1996) On the enhanced stability of the guanine-cytosine base-pair radical cation. J Am Chem Soc 118 7574-7577... 

J. Gu et al., H-bonding patterns in the platinated guanine-cytosine base pair and guanine-cytosine-guanine-cytosine base tetrad An electron density deformation analysis and aim study. J. Am. Chem. Soc. 126, 12651-12660 (2004)... 

Since coiled chains of proteins are known to uncurl because of ionic repulsions when ionization occurs, Reid (1957) suggested that excited state dissociation acts as a trigger in rapid biological processes. The 7-azaindole dimer, which undergoes photo-induced double proton transfer (see Section 4), has similarities to the adenine-thymine and guanine-cytosine base pairs of DNA. Its excited state proton transfers have been proposed as possible mechanisms of mutagenesis (Ingram and El-Bayoumi, 1974). 

The anionic Watson-Crick guanine-cytosine base pair behaves in a different manner [75], Namely, out of several possible configurations, differing with the position of proton(s), the geometry with proton transferred from the N1 atom of guanine to the N3 atom of cytosine turned out to be the global minimum. This structure is more stable than the Watson-Crick anion by 2.9 (B3LYP) and... 

The adenine-cytosine base pair was not observed experimentally except in a mismatch oligonucleotide (Part III, Chap. 20) and probably has no significance in biology except in mutation events. 

Uracil-cytosine base pairs are mixed pyrimidine-pyrimidine complexes, which are biologically less or even not at all important. There are six two-bond configurations, of which only CU52, CU62 could occur in nucleic acids. 

Zhanpeisov, N. U. Sponer, J. Leszczynski, J. Reverse Watson-Crick isocytosine-cytosine and guanine-cytosine base pairs stabilized by the formation of the minor tautomers of bases. An ab initio study in the gas phase and in a water cluster, J. Phys. Ghent. A 1998,102,10374-10379. 

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