Proton transfer reactions of nucleic acid bases: A semiempirical molecular orbital study

Divi Venkateswarlu; R. H.Duncan Lyngdoh

doi:10.1007/BF02884440

Proton transfer reactions of nucleic acid bases: A semiempirical molecular orbital study

Divi Venkateswarlu, R. H.Duncan Lyngdoh

North-Eastern Hill University

Research output: Contribution to journal › Article › peer-review

Abstract

The possibilities open for tautomerism, for protonation and for deprotonation in the five nucleic acid bases are examined theoretically using the semiempirical AM1 SCF-MO methodology. The tautomers predicted to be the most stable, other than the usual forms, all involve proton shifts to adjacent sites. The sites predicted to be the most favourable for protonation are the N⁷-G, N³-A, N³-C, O⁴-T and O⁴-U positions of guanine, adenine, cytosine, thymine and uracil respectively. The protons predicted to be the most acidic for each base are the N¹-G, N⁹-A, N¹-C, N³-T and N³-U protons. These predictions accord well with the conclusions drawn from experimental work so far as assignments of acidic protons and basic sites for the particular bases are concerned. However, the relative feasibility of these reactions for the different bases is not well predicted by these gas-phase calculations.

Original language	English
Pages (from-to)	221-231
Number of pages	11
Journal	Proceedings of the Indian Academy of Sciences - Chemical Sciences
Volume	107
Issue number	3
DOIs	https://doi.org/10.1007/BF02884440
State	Published - Jun 1995
Externally published	Yes

Keywords

Nucleic acid bases
molecular orbital calculations
protic acid-base equilibria
tautomerism

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10.1007/BF02884440

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title = "Proton transfer reactions of nucleic acid bases: A semiempirical molecular orbital study",

abstract = "The possibilities open for tautomerism, for protonation and for deprotonation in the five nucleic acid bases are examined theoretically using the semiempirical AM1 SCF-MO methodology. The tautomers predicted to be the most stable, other than the usual forms, all involve proton shifts to adjacent sites. The sites predicted to be the most favourable for protonation are the N7-G, N3-A, N3-C, O4-T and O4-U positions of guanine, adenine, cytosine, thymine and uracil respectively. The protons predicted to be the most acidic for each base are the N1-G, N9-A, N1-C, N3-T and N3-U protons. These predictions accord well with the conclusions drawn from experimental work so far as assignments of acidic protons and basic sites for the particular bases are concerned. However, the relative feasibility of these reactions for the different bases is not well predicted by these gas-phase calculations.",

keywords = "Nucleic acid bases, molecular orbital calculations, protic acid-base equilibria, tautomerism",

author = "Divi Venkateswarlu and Lyngdoh, \{R. H.Duncan\}",

year = "1995",

month = jun,

doi = "10.1007/BF02884440",

language = "English",

volume = "107",

pages = "221--231",

journal = "Proceedings of the Indian Academy of Sciences - Chemical Sciences",

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TY - JOUR

T1 - Proton transfer reactions of nucleic acid bases

T2 - A semiempirical molecular orbital study

AU - Venkateswarlu, Divi

AU - Lyngdoh, R. H.Duncan

PY - 1995/6

Y1 - 1995/6

N2 - The possibilities open for tautomerism, for protonation and for deprotonation in the five nucleic acid bases are examined theoretically using the semiempirical AM1 SCF-MO methodology. The tautomers predicted to be the most stable, other than the usual forms, all involve proton shifts to adjacent sites. The sites predicted to be the most favourable for protonation are the N7-G, N3-A, N3-C, O4-T and O4-U positions of guanine, adenine, cytosine, thymine and uracil respectively. The protons predicted to be the most acidic for each base are the N1-G, N9-A, N1-C, N3-T and N3-U protons. These predictions accord well with the conclusions drawn from experimental work so far as assignments of acidic protons and basic sites for the particular bases are concerned. However, the relative feasibility of these reactions for the different bases is not well predicted by these gas-phase calculations.

AB - The possibilities open for tautomerism, for protonation and for deprotonation in the five nucleic acid bases are examined theoretically using the semiempirical AM1 SCF-MO methodology. The tautomers predicted to be the most stable, other than the usual forms, all involve proton shifts to adjacent sites. The sites predicted to be the most favourable for protonation are the N7-G, N3-A, N3-C, O4-T and O4-U positions of guanine, adenine, cytosine, thymine and uracil respectively. The protons predicted to be the most acidic for each base are the N1-G, N9-A, N1-C, N3-T and N3-U protons. These predictions accord well with the conclusions drawn from experimental work so far as assignments of acidic protons and basic sites for the particular bases are concerned. However, the relative feasibility of these reactions for the different bases is not well predicted by these gas-phase calculations.

KW - Nucleic acid bases

KW - molecular orbital calculations

KW - protic acid-base equilibria

KW - tautomerism

UR - https://www.scopus.com/pages/publications/23744466971

U2 - 10.1007/BF02884440

DO - 10.1007/BF02884440

M3 - Article

SN - 0253-4134

VL - 107

SP - 221

EP - 231

JO - Proceedings of the Indian Academy of Sciences - Chemical Sciences

JF - Proceedings of the Indian Academy of Sciences - Chemical Sciences

IS - 3

ER -

Proton transfer reactions of nucleic acid bases: A semiempirical molecular orbital study

Abstract

Keywords

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