Tunnelling Spectroscopy and Dynamics of CH3 in a Homologous Series of Ketones

Horsewill, A.J.; Green, R. M.; Alsanoosi, A. M.

doi:10.1007/978-3-642-71914-1_5

Cited by 6 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These interactions can be either of intra-or intermolecular nature. 23,47 Matrix deuteration might alter the methyl group's local environment and therefore the interactions governing the rotation barrier. Usually this so-called ''external isotope effect'' has only a weak impact on the rotation barrier.…”

Section: Tunneling Eseem Upon Matrix Deuterationmentioning

confidence: 99%

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Eggeling

Soetbeer

Ibáñez

et al. 2023

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

Section: Tunneling Eseem Upon Matrix Deuterationmentioning

confidence: 99%

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Eggeling

Soetbeer

Ibáñez

et al. 2023

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…42 The same value, 3.0 kcal/mol, has been obtained for the barrier height in CH 3 -(CH 2 ) 2 -CO-(CH 2 ) 2 -CH 3 . 43 In a number of studies activation energies have been determined for individual amino acids, mainly by solid-state NMR. 26,27,44 Measurements have been also done on proteins selectively labeled with respect to certain types of amino acids.…”

Section: J(ω)mentioning

confidence: 99%

Methyl Rotation Barriers in Proteins from ²H Relaxation Data. Implications for Protein Structure

et al. 2007

View full text Add to dashboard Cite

Side-chain 2H and backbone 15N relaxation data have been collected at multiple temperatures in the samples of the SH3 domain from alpha-spectrin. Combined analyses of the data allowed for determination of the temperature-dependent correlation times tauf characterizing fast methyl motion. Molecular dynamics simulations confirmed that tauf are dominated by methyl rotation; the corresponding activation energies approximate methyl rotation barriers. For 33 methyl groups in the alpha-spectrin SH3 domain the average barrier height was thus determined to be 2.8 +/- 0.9 kcal/mol. This value is deemed representative of the "fluid" hydrophobic protein core where some barriers are increased and others are lowered because of the contacts with surrounding atoms, but there is no local order that could produce systematically higher (lower) barriers. For comparison, the MD simulation predicts the average barrier of 3.1 kcal/mol (calculated via the potential of mean force) or 3.4-3.5 kcal/mol (rigid barriers after appropriate averaging over multiple MD snapshots). The latter result prompted us to investigate rigid methyl rotation barriers in a series of NMR structures from the Protein Databank. In most cases the barriers proved to be higher than expected, 4-6 kcal/mol. To a certain degree, this is caused by tight packing of the side chains in the NMR structures and stems from the structure calculation procedure where the coordinates are first annealed toward the temperature of 0 K and then subjected to energy minimization. In several cases the barriers >10 kcal/mol are indicative of van der Waals violations. The notable exceptions are (i) the structures solved using the GROMOS force field where tight methyl packing is avoided (3.0-3.6 kcal/mol) and (ii) the structure solved by means of the dynamic ensemble refinement method (Lindorff-Larsen, K.; Best, R. B.; DePristo, M. A.; Dobson, C. M.; Vendruscolo, M. Nature 2005, 433, 128) (3.5 kcal/mol). These results demonstrate that methyl rotation barriers, derived from the experiments that are traditionally associated with studies of protein dynamics, can be also used in the context of structural work. This is particularly interesting in view of the recent efforts to incorporate dynamics data in the process of protein structure elucidation.

show abstract

“…Systematic studies of series of compounds differing only in a few well-defined properties have been found to be very useful. Such investigations were performed for acetates, methylbenzenes, the halomesitylenes, hexaammines and metal hexaammines, alkanes, , ketones, , tetramethyl metal compounds, organometallic methyl−tin materials, ammonium hexahalometalates, ammonium in alkali halides, methane in rare gas matrices and hydrogen-substituted metal carbonyls. , The relevant references are found in the corresponding tables (see section 5).…”

Section: 8 Systematic Studies and New Materialsmentioning

confidence: 99%

Rotational Tunneling and Neutron Spectroscopy: A Compilation

1997

View full text Add to dashboard Cite

Tunnelling Spectroscopy and Dynamics of CH3 in a Homologous Series of Ketones

Cited by 6 publications

References 9 publications

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Methyl Rotation Barriers in Proteins from ²H Relaxation Data. Implications for Protein Structure

Rotational Tunneling and Neutron Spectroscopy: A Compilation

Contact Info

Product

Resources

About

Tunnelling Spectroscopy and Dynamics of CH3 in a Homologous Series of Ketones

Cited by 6 publications

References 9 publications

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Quantifying methyl tunneling induced (de)coherence of nitroxides in glassy ortho-terphenyl at low temperatures

Methyl Rotation Barriers in Proteins from 2H Relaxation Data. Implications for Protein Structure

Rotational Tunneling and Neutron Spectroscopy: A Compilation

Contact Info

Product

Resources

About

Methyl Rotation Barriers in Proteins from ²H Relaxation Data. Implications for Protein Structure