Cytosine electrostatic potentials

Cyclopentenones. from 1.4-diketones. 886-887 Cyclopropane, angle strain in, 115 bent bonds in. 115 from alkenes. 227-229 molecular model of, 111. 115 strain energy of, 114 torsional strain in, 115 Cystathionine, cysteine from. 1177 Cysteine, biosynthesis of, 1177 disulfide bridges from, 1029 structure and properties of, 1018 Cytosine, electrostatic potential map of, 1104... 

Bonaccorsi, R., A. Pullman, E. Scrocco, and J. Tomasi. 1972b. The Molecular Electrostatic Potentials for the Nucleic Acid Bases Adenine, Thymine and Cytosine. Theor. Chim. Acta 24, 51. 

Fig. 2. Electrostatic potential maps for cytosine in the ring plane (kj/mol) a calculated with AMI b calculated with STO-3G. (Reproduced from [40] copyright-John Wiley Sons)...

As a last example of shape of electrostatic potential, we report here some results for a purinic compound, adenine (XXII). Analogous results for other nucleic acid components, thymine and cytosine, may be found in the source paper29). 

For illustrative purposes, Fig. 1 shows our computed electrostatic potentials on the surfaces of cytosine (1) and guanine (2). Only three ranges of values are given however, this could of course be increased by using various colors. 

Figure 1 Electrostatic potentials on the molecular surfaces of (a) cytosine, 1, and (b) guanine, 2, computed at the Hartree-Fock 6-31G level. Color ranges, in kcal/mol red, more positive than 17 blue, more negative than —20 (see legend). The relative positions of the molecules are such that the portions that hydrogen bond are facing each other, showing how the extended positive and negative regions will interact. (See color plate at end of chapter.)...

Figure 1 shows a calculated two-dimensional electrostatic potential contour map of cytosine (1), in kcal/mol, in the plane of the ring. An extensive negative region is associated with N3 and Og, with three local minima. These V ,i are near N3 and Og, with values of - 85, - 70, and - 61 kcal/mol the... 

The electrostatic potentials of the nucleic acid bases [adenine (9), guanine (10), cytosine (1), and thymine (11)] were first studied in the early 1970s. Each of these molecules has several likely sites for electrophilic attack V(r)... 

Fig 217 Electrostatic potential contours around cytosine Negative contours are dashed, the zero contour is bold. The minima near N3 and O are marked... 

Electrostatic potential maps illustrating hydrogen bonding between thymine and adenine (a) and cytosine and guanine (b). The oxygens are red, and the nitrogens are blue. 

Bonaccorsi R, Pullman A, Scrocco E, Tomasi J (1972) The molecular electrostatic potentials for the nucleic acid bases adenine, thymine, and cytosine. Theor Chim Acta 24 51-60. doi 10.1007/BF00528310... 

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