correlation analogous to the correlation between ED and hydrogen bond length

Correlation analogous to the correlation between ed

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correlation, analogous to the correlation between ED and hydrogen bond length. The correlation coefficient for the ED ( r values) and hydrogen bond length of the most stable GG–DC, GG–PC and GG–TR drug-interacted complex were found to be 0.972, 0.996 and 0.982, respectively, at B3LYP/6-311 þ G** level of theory. Similarly, corre- lation coefficient for the Laplacian of ED ( 7 2 r ) and hydrogen bond length of the above-mentioned drug- interacted complexes were found to be 0.963, 0.976 and 0.994 at B3LYP/6-311 þ G** level of theory. In addition, the correlation coefficient for ED ( r ) and Laplacian of ED ( 7 2 r ) values at B3LYP/6-311 þ G** level of theory of the most stable (GG–DC, GG–PR and GG–TR) drug- interacted complexes were observed to be 0.959, 0.985 and 0.982, and the correlation graphs are shown in supplementary Figures S2–S4. 3.3 NBO analysis Among the theoretical methods, NBO analysis is a unique approach to evaluate the delocalisation effects. [59,60] In this analysis, stabilisation energy E (2) related to the delocalisation trend of electrons from donor to acceptor orbitals was calculated via perturbation theory. If the stabilisation energy E (2) between donor bonding orbital and the acceptor orbital is large, then there is a strong interaction between them. For each donor orbital ( i ) and Table 2. The isolated and drug–DNA complexes frontier MOs energies are calculated at B3LYP/6-311 þ G** level of theory. Drug–DNA complexes Isolated base pairs DC–DNA complexes PR–DNA complexes TR–DNA complexes S. no. Base pairs HOMO LUMO HOMO LUMO HOMO LUMO HOMO LUMO 1 GC 2 6.2 2 0.984 2 5.126 2 1.722 2 5.525 2 1.267 2 4.96 2 2.946 2 AT 2 6.194 2 1.441 2 5.372 2 2.036 2 5.558 2 1.475 2 5.805 2 1.602 3 GG 2 5.873 2 1.745 2 4.979 2 1.723 2 5.493 2 1.069 2 4.962 2 2.947 4 CC 2 5.702 2 1.697 2 5.918 2 1.926 2 5.637 2 1.351 2 5.231 2 1.605 5 AA 2 5.98 2 1.31 2 5.61 2 2.148 2 5.739 2 1.216 2 5.825 2 0.867 6 TT 2 6.814 2 1.48 2 5.538 2 1.512 2 6.319 2 1.453 2 6.393 2 1.574 DC* 2 5.94 2 2.011 PR* 2 6.377 2 1.227 TR* 2 6.739 2 0.698 *Isolated drug molecules. 12 R. Shankar et al. Downloaded by [Bharathiar University] at 22:01 02 January 2015
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Table 3. Occupation number of the proton donor s *(X Z H), acceptor lone pair n ( y ), the hydrogen bond stabilisation energy E (2) , ED, Laplacian of ED and the bond ellipticity corresponds to hydrogen bonds in (AT, GC, GG, CC, AA, and TT with DC) drug-interacting complexes at B3LYP/6-31 þ G** level of theory. Bonding Hydrogen-bond length in A ˚ Donor s *(X Z H) Acceptor n ( y ) E (2) in kcal/mol r in a.u. 7 2 r in a.u. 1 in a.u. AA Z DC N 6 Z H 6b · · · N 1 2.274 0.022 1.900 5.36 0.016 0.045 0.054 N 6 Z H 6b · · · DO 11 1.834 0.050 1.949 6.90 0.033 0.097 0.040 N 6 Z H 6a · · · DO 11 1.951 0.029 1.949 9.52 0.022 0.073 0.013 DN 12 Z DH 12b · · · N 1 2.057 0.046 1.885 13.99 0.024 0.057 0.068 DN 12 Z DH 12a · · · DN 6 2.183 0.026 1.919 5.21 0.018 0.057 0.018 AT Z DC N 10 Z H 6a · · · DO 11 1.931 0.035 1.946 7.86 0.025 0.075 0.028 DN 12 Z DH 12a · · · O 6 1.898 0.063 1.946 14.55 0.034 0.098 0.036 DN 12 Z DH 12b · · · DN 7 1.953 0.045 1.925 15.23 0.030 0.083 0.057 N 1 Z H 1 · · · DO 11 1.813 0.062 1.932 14.56 0.028 0.081 0.036 DC 10 Z DH 10a · · · DN 6 2.551 0.011 1.926 1.39 0.019 0.060 0.218 CC Z DC N 1 Z H 1 · · · DO 11 2.010 0.035 1.952 5.61 0.076 0.079 0.045 N 6 Z H 6b · · · DO 11 1.856 0.039 1.882 7.91 0.081 0.098 0.103 N 1 Z H 1 · · · N 6 2.030 0.048 1.782 14.08 0.023 0.063 0.050 DN 12 Z DH 12a · · · O 2 1.894 0.039 1.960 9.04 0.045 0.090 0.102 DN 12 Z DH 12b · · · DN 7 1.931 0.047 1.923 16.35 0.025 0.109 0.130 DC 10 Z DH 10a · · · DN 6 2.553 0.011 1.925 1.32 0.019 0.060 0.118 GC Z DC N 1 Z H 1 · · · DO 11 1.806 0.048 1.906 15.04 0.031 0.113 0.035 N 2 Z H 2a · · · DO 11 2.056 0.032 1.946 3.89 0.021 0.064 0.054 N 2 Z H 2a
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