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Nature. 2015 Jan 8;517(7533):227-30. doi: 10.1038/nature14043. Epub 2014 Dec 10.

The heat released during catalytic turnover enhances the diffusion of an enzyme.

Author information

1
California Institute for Quantitative Biosciences, QB3, University of California, Berkeley, California 94720, USA.
2
1] California Institute for Quantitative Biosciences, QB3, University of California, Berkeley, California 94720, USA [2] Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, 1058 Santiago, Chile.
3
Department of Physics, Indiana University-Purdue University Indianapolis (IUPUI), Indiana 46202, USA.
4
1] California Institute for Quantitative Biosciences, QB3, University of California, Berkeley, California 94720, USA [2] Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
5
1] Department of Physics, Indiana University-Purdue University Indianapolis (IUPUI), Indiana 46202, USA [2] Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indiana 46202, USA.
6
1] California Institute for Quantitative Biosciences, QB3, University of California, Berkeley, California 94720, USA [2] Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA [3] Jason L. Choy Laboratory of Single-Molecule Biophysics and Department of Physics, University of California, Berkeley, California 94720, USA [4] Department of Chemistry, University of California, Berkeley, California 94720, USA [5] Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA [6] Kavli Energy Nano Sciences Institute, University of California, Berkeley and Lawrence Berkeley National Laboratory, California 94720, USA.

Abstract

Recent studies have shown that the diffusivity of enzymes increases in a substrate-dependent manner during catalysis. Although this observation has been reported and characterized for several different systems, the precise origin of this phenomenon is unknown. Calorimetric methods are often used to determine enthalpies from enzyme-catalysed reactions and can therefore provide important insight into their reaction mechanisms. The ensemble averages involved in traditional bulk calorimetry cannot probe the transient effects that the energy exchanged in a reaction may have on the catalyst. Here we obtain single-molecule fluorescence correlation spectroscopy data and analyse them within the framework of a stochastic theory to demonstrate a mechanistic link between the enhanced diffusion of a single enzyme molecule and the heat released in the reaction. We propose that the heat released during catalysis generates an asymmetric pressure wave that results in a differential stress at the protein-solvent interface that transiently displaces the centre-of-mass of the enzyme (chemoacoustic effect). This novel perspective on how enzymes respond to the energy released during catalysis suggests a possible effect of the heat of reaction on the structural integrity and internal degrees of freedom of the enzyme.

PMID:
25487146
PMCID:
PMC4363105
DOI:
10.1038/nature14043
[Indexed for MEDLINE]
Free PMC Article

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