Estimating Relative Disulfide Energies: An Accurate Ab Initio Potential Energy Surface
Date
2010
Authors
Haworth, Naomi
Liu, Jason Y
Fan, Samuel W
Gready, Jill
Wouters, M
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CSIRO Publishing
Abstract
Disulfide torsional energy, a good predictor of disulfide redox potential in proteins, may be estimated by interpolation on a potential energy surface (PES) describing the twisting of diethyl disulfide through its three central dihedral angles. Here we update PES calculations at the M05-2X level of theory with the 6-31G(d) basis set. Although the surface shows no qualitative differences from an earlier MP2(full) PES, energy differences greater than 1 kJ mol-1 were seen for conformations with Ξ2 between -60° and 30°, or with Ξ3 below 60° or above 130°. This is particularly significant for highly strained disulfides that are likely to be spontaneously reduced by mechanical means. In benchmarking against the high-level G3X method, M05-2X showed significantly reduced root mean squared deviation compared with MP2(full) (1.0 versus 2.0 kJ mol-1 respectively). Results are incorporated into a web application that calculates relative torsional energies from disulfide dihedral angles (http://www.sbinf. org/applications/pes.html).
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Keywords: Ab initio potential energy surface; Basis sets; Diethyl disulfide; Dihedral angles; Energy differences; Highly strained; Qualitative differences; Redox potentials; Root mean squared deviations; Torsional energies; WEB application; Potential energy; Quantu
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Australian Journal of Chemistry
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Journal article
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2037-12-31
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