Isotope Substitution of Promiscuous Alcohol Dehydrogenase Reveals the Origin of Substrate Preference in the Transition State.

Autor: Behiry EM; School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT, UK., Ruiz-Pernia JJ; Departament de Química Física, Universitat de València, 46100, Burjassot, Spain., Luk L; School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT, UK., Tuñón I; Departament de Química Física, Universitat de València, 46100, Burjassot, Spain., Moliner V; Departament de Química Física i Analítica, Universitat Jaume I, 12071, Castelló, Spain., Allemann RK; School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT, UK.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2018 Mar 12; Vol. 57 (12), pp. 3128-3131. Date of Electronic Publication: 2018 Feb 19.
DOI: 10.1002/anie.201712826
Abstrakt: The origin of substrate preference in promiscuous enzymes was investigated by enzyme isotope labelling of the alcohol dehydrogenase from Geobacillus stearothermophilus (BsADH). At physiological temperature, protein dynamic coupling to the reaction coordinate was insignificant. However, the extent of dynamic coupling was highly substrate-dependent at lower temperatures. For benzyl alcohol, an enzyme isotope effect larger than unity was observed, whereas the enzyme isotope effect was close to unity for isopropanol. Frequency motion analysis on the transition states revealed that residues surrounding the active site undergo substantial displacement during catalysis for sterically bulky alcohols. BsADH prefers smaller substrates, which cause less protein friction along the reaction coordinate and reduced frequencies of dynamic recrossing. This hypothesis allows a prediction of the trend of enzyme isotope effects for a wide variety of substrates.
(© 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)
Databáze: MEDLINE
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