TY - JOUR
T1 - Heats of formation of the amino acids re-examined by means of W1-F12 and W2-F12 theories
AU - Karton, Amir
AU - Yu, Li-Juan
AU - Kesharwani, Manoj K.
AU - Martin, Jan M. L.
N1 - Lise Meitner-Minerva Center for Computational Quantum Chemistry; Helen and Martin Kimmel Center for Molecular Design; Weizmann AERI (Alternative Energy Research Initiative); University of North Texas; Australian Research Council (ARC) [DE140100311]JMLM is the Baroness Thatcher Professor of Chemistry at the Weizmann Institute of Science and acknowledges partial financial support from the Lise Meitner-Minerva Center for Computational Quantum Chemistry and the Helen and Martin Kimmel Center for Molecular Design. This research was supported in part by the Weizmann AERI (Alternative Energy Research Initiative) and by a startup grant from the University of North Texas from which the Martin group Linux cluster was purchased. The authors would like to thank Dr. David Hrovat for assistance with procurement and management of the latter. A. K. is the recipient of an Australian Research Council (ARC) Discovery Early Career Researcher Award (project number: DE140100311). We also acknowledge the generous allocation of computing time from the National Computational Infrastructure (NCI) National Facility and the support of iVEC through the use of advanced computing resources located at iVEC@UWA.
PY - 2014/6
Y1 - 2014/6
N2 - We have obtained accurate heats of formation for the twenty natural amino acids by means of explicitly correlated high-level thermochemical procedures. Our best theoretical heats of formation, obtained by means of the ab initio W1-F12 and W2-F12 thermochemical protocols, differ significantly (RMSD = 2.3 kcal/mol, maximum deviation 4.6 kcal/mol) from recently reported values using the lower-cost G3(MP2) method. With the more recent G4(MP2) procedure, RMSD drops slightly to 1.8 kcal/mol, while full G4 theory offers a more significant improvement to 0.72 kcal/mol (max. dev. 1.4 kcal/mol for glutamine). The economical G4(MP2)-6X protocol performs equivalently at RMSD = 0.71 kcal/mol (max. dev. 1.6 kcal/mol for arginine and glutamine). Our calculations are in excellent agreement with experiment for glycine, alanine and are in excellent agreement with the recent revised value for methionine, but suggest revisions by several kcal/mol for valine, proline, phenylalanine, and cysteine, in the latter case confirming a recent proposed revision. Our best heats of formation at 298 K (ΔHof,298) are as follows: at the W2-F12 level: glycine -94.1, alanine -101.5, serine -139.2, cysteine -94.5, and methionine -102.4 kcal/mol, and at the W1-F12 level: arginine -98.8, asparagine -146.5, aspartic acid -189.6, glutamine -151.0, glutamic acid -195.5, histidine -69.8, isoleucine -118.3, leucine -118.8, lysine -110.0, phenylalanine -76.9, proline -92.8, threonine -149.0, and valine -113.6 kcal/mol. For the two largest amino acids, an average over G4, G4(MP2)-6X, and CBS-QB3 yields best estimates of -58.4 kcal/mol for tryptophan, and of -117.5 kcal/mol for tyrosine. For glycine, we were able to obtain a "quasi-W4" result corresponding to TAEe = 968.1, TAE0 = 918.6, ΔHof,298 = -90:0, and ΔHof,298 = -94:0 kcal/mol.
AB - We have obtained accurate heats of formation for the twenty natural amino acids by means of explicitly correlated high-level thermochemical procedures. Our best theoretical heats of formation, obtained by means of the ab initio W1-F12 and W2-F12 thermochemical protocols, differ significantly (RMSD = 2.3 kcal/mol, maximum deviation 4.6 kcal/mol) from recently reported values using the lower-cost G3(MP2) method. With the more recent G4(MP2) procedure, RMSD drops slightly to 1.8 kcal/mol, while full G4 theory offers a more significant improvement to 0.72 kcal/mol (max. dev. 1.4 kcal/mol for glutamine). The economical G4(MP2)-6X protocol performs equivalently at RMSD = 0.71 kcal/mol (max. dev. 1.6 kcal/mol for arginine and glutamine). Our calculations are in excellent agreement with experiment for glycine, alanine and are in excellent agreement with the recent revised value for methionine, but suggest revisions by several kcal/mol for valine, proline, phenylalanine, and cysteine, in the latter case confirming a recent proposed revision. Our best heats of formation at 298 K (ΔHof,298) are as follows: at the W2-F12 level: glycine -94.1, alanine -101.5, serine -139.2, cysteine -94.5, and methionine -102.4 kcal/mol, and at the W1-F12 level: arginine -98.8, asparagine -146.5, aspartic acid -189.6, glutamine -151.0, glutamic acid -195.5, histidine -69.8, isoleucine -118.3, leucine -118.8, lysine -110.0, phenylalanine -76.9, proline -92.8, threonine -149.0, and valine -113.6 kcal/mol. For the two largest amino acids, an average over G4, G4(MP2)-6X, and CBS-QB3 yields best estimates of -58.4 kcal/mol for tryptophan, and of -117.5 kcal/mol for tyrosine. For glycine, we were able to obtain a "quasi-W4" result corresponding to TAEe = 968.1, TAE0 = 918.6, ΔHof,298 = -90:0, and ΔHof,298 = -94:0 kcal/mol.
UR - http://www.scopus.com/inward/record.url?scp=84899645082&partnerID=8YFLogxK
U2 - 10.1007/s00214-014-1483-8
DO - 10.1007/s00214-014-1483-8
M3 - مقالة
SN - 1432-881X
VL - 133
SP - 1
EP - 15
JO - Theoretical Chemistry Accounts
JF - Theoretical Chemistry Accounts
IS - 6
M1 - 1483
ER -