Ab initio studies of 2,4-diamino triazine and its complexes with ligands: a model for inhibitor-active site interactions of dihydrofolate reductase
The protonation energies of 2,4-diamino triazine, an inhibitor of the therapeutic target dihydrofolate reductase, has been calculated using ab initio (Hartree-Fock) calculations. It is found that N1 (see Fig. 1) exhibits the highest proton affinity (261.6 kcal/mol) by comparison with other inhibitor...
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Published in | Cancer investigation Vol. 12; no. 5; p. 469 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
England
1994
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Subjects | |
Online Access | Get more information |
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Summary: | The protonation energies of 2,4-diamino triazine, an inhibitor of the therapeutic target dihydrofolate reductase, has been calculated using ab initio (Hartree-Fock) calculations. It is found that N1 (see Fig. 1) exhibits the highest proton affinity (261.6 kcal/mol) by comparison with other inhibitor protonation sites. The energies of binding of the formate ion and formamide (as models for the amino acid residues in the active site of dihydrofolate reductase) to neutral and protonated 2,4-diamino triazine are also obtained. The highest binding energies are featured by the complex formed from a formate attached to the N4 and N1 protonated forms of the triazine. However, as N4 has a comparatively low proton affinity (195.0 kcal/mol), it is unlikely that an interaction of this nature would prevail. On the other hand, the formate-protonated N1 interaction is similar to the structures identified by X-ray crystallography of enzyme-triazine complexes. |
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ISSN: | 0735-7907 1532-4192 |
DOI: | 10.3109/07357909409021405 |