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- PMID: 11457011
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Article: Proton migration and tautomerism in protonated triglycine
Title | Proton migration and tautomerism in protonated triglycine |
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Authors | |
Issue Date | 2001 |
Publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html |
Citation | Journal Of The American Chemical Society, 2001, v. 123 n. 13, p. 3006-3012 How to Cite? |
Abstract | Proton migration in protonated glycylglycylglycine (GGG) has been investigated by using density functional theory at the B3LYP/6-31++G(d,p) level of theory. On the protonated GGG energy hypersurface 19 critical points have been characterized, 11 as minima and 8 as first-order saddle points. Transition state structures for interconversion between eight of these minima are reported, starting from a structure in which there is protonation at the amino nitrogen of the N-terminal glycyl residue following the migration of the proton until there is fragmentation into protonated 2-aminomethyl-5-oxazolone (the b 2 ion) and glycine. Individual free energy barriers are small, ranging from 4.3 to 18.1 kcal mol -1. The most favorable site of protonation on GGG is the carbonyl oxygen of the N-terminal residue. This isomer is stabilized by a hydrogen bond of the type O-H···N with the N-terminal nitrogen atom, resulting in a compact five-membered ring. Another oxygen-protonated isomer with hydrogen bonding of the type O-H···O, resulting in a seven-membered ring, is only 0.1 kcal mol -1 higher in free energy. Protonation on the N-terminal nitrogen atom produces an isomer that is about 1 kcal mol -1 higher in free energy than isomers resulting from protonation on the carbonyl oxygen of the N-terminal residue. The calculated energy barrier to generate the b 2 ion from protonated GGG is 32.5 kcal mol -1 via TS(6→7). The calculated basicity and proton affinity of GGG from our results are 216.3 and 223.8 kcal mol -1, respectively, These values are 3-4 kcal mol -1 lower than those from previous calculations and are in excellent agreement with recently revised experimental values. |
Persistent Identifier | http://hdl.handle.net/10722/167679 |
ISSN | 2023 Impact Factor: 14.4 2023 SCImago Journal Rankings: 5.489 |
ISI Accession Number ID | |
References |
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Rodriquez, CF | en_US |
dc.contributor.author | Cunje, A | en_US |
dc.contributor.author | Shoeib, T | en_US |
dc.contributor.author | Chu, IK | en_US |
dc.contributor.author | Hopkinson, AC | en_US |
dc.contributor.author | Siu, KWM | en_US |
dc.date.accessioned | 2012-10-08T03:09:54Z | - |
dc.date.available | 2012-10-08T03:09:54Z | - |
dc.date.issued | 2001 | en_US |
dc.identifier.citation | Journal Of The American Chemical Society, 2001, v. 123 n. 13, p. 3006-3012 | en_US |
dc.identifier.issn | 0002-7863 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/167679 | - |
dc.description.abstract | Proton migration in protonated glycylglycylglycine (GGG) has been investigated by using density functional theory at the B3LYP/6-31++G(d,p) level of theory. On the protonated GGG energy hypersurface 19 critical points have been characterized, 11 as minima and 8 as first-order saddle points. Transition state structures for interconversion between eight of these minima are reported, starting from a structure in which there is protonation at the amino nitrogen of the N-terminal glycyl residue following the migration of the proton until there is fragmentation into protonated 2-aminomethyl-5-oxazolone (the b 2 ion) and glycine. Individual free energy barriers are small, ranging from 4.3 to 18.1 kcal mol -1. The most favorable site of protonation on GGG is the carbonyl oxygen of the N-terminal residue. This isomer is stabilized by a hydrogen bond of the type O-H···N with the N-terminal nitrogen atom, resulting in a compact five-membered ring. Another oxygen-protonated isomer with hydrogen bonding of the type O-H···O, resulting in a seven-membered ring, is only 0.1 kcal mol -1 higher in free energy. Protonation on the N-terminal nitrogen atom produces an isomer that is about 1 kcal mol -1 higher in free energy than isomers resulting from protonation on the carbonyl oxygen of the N-terminal residue. The calculated energy barrier to generate the b 2 ion from protonated GGG is 32.5 kcal mol -1 via TS(6→7). The calculated basicity and proton affinity of GGG from our results are 216.3 and 223.8 kcal mol -1, respectively, These values are 3-4 kcal mol -1 lower than those from previous calculations and are in excellent agreement with recently revised experimental values. | en_US |
dc.language | eng | en_US |
dc.publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html | en_US |
dc.relation.ispartof | Journal of the American Chemical Society | en_US |
dc.subject.mesh | Energy Transfer | en_US |
dc.subject.mesh | Isomerism | en_US |
dc.subject.mesh | Oligopeptides - Chemistry - Metabolism | en_US |
dc.subject.mesh | Protein Binding | en_US |
dc.subject.mesh | Protons | en_US |
dc.subject.mesh | Quantum Theory | en_US |
dc.title | Proton migration and tautomerism in protonated triglycine | en_US |
dc.type | Article | en_US |
dc.identifier.email | Chu, IK:ivankchu@hku.hk | en_US |
dc.identifier.authority | Chu, IK=rp00683 | en_US |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.doi | 10.1021/ja0015904 | en_US |
dc.identifier.pmid | 11457011 | - |
dc.identifier.scopus | eid_2-s2.0-0034829543 | en_US |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-0034829543&selection=ref&src=s&origin=recordpage | en_US |
dc.identifier.volume | 123 | en_US |
dc.identifier.issue | 13 | en_US |
dc.identifier.spage | 3006 | en_US |
dc.identifier.epage | 3012 | en_US |
dc.identifier.isi | WOS:000167806300009 | - |
dc.publisher.place | United States | en_US |
dc.identifier.scopusauthorid | Rodriquez, CF=7004085075 | en_US |
dc.identifier.scopusauthorid | Cunje, A=6602535833 | en_US |
dc.identifier.scopusauthorid | Shoeib, T=6603516521 | en_US |
dc.identifier.scopusauthorid | Chu, IK=7103327484 | en_US |
dc.identifier.scopusauthorid | Hopkinson, AC=15067169300 | en_US |
dc.identifier.scopusauthorid | Siu, KWM=35312218500 | en_US |
dc.identifier.issnl | 0002-7863 | - |