Journal article
Picosecond Active‐Site Dynamics Correlate with the Temperature Dependence of KIEs in Enzyme‐Catalyzed Hydride Transfer
The FASEB journal, Vol.32(S1), pp.475.4-475.4
04/2018
DOI: 10.1096/fasebj.2018.32.1_supplement.475.4
Abstract
Picosecond time scale motions in enzymes have often been invoked to explain the temperature dependence of primary kinetic isotope effects (KIE) in enzyme‐catalyzed hydride transfer reactions, but these experiments come short of actually measuring the dynamics in these systems on timescales relevant to the making and breaking of bonds. Similar to other enzymes, wild‐type Formate dehydrogenase (FDH) from Candida boidinii exhibits a temperature independent KIE that becomes temperature dependent when space is opened up in the active site via mutation of the V123 residue to alanine and glycine. Transition state analog complexes of FDH bound to azide offer a unique opportunity to investigate how these mutations influence active site dynamics. With a combination of 2D IR spectroscopy, X‐ray crystallography, and molecular dynamic simulations, we report a comprehensive view of fast motions of the active site and their relationship to the hydride transfer. Azide bound to FDH exhibits oscillatory frequency fluctuations on the ps timescale, and the amplitude of these fluctuations increases when the active site space increases in correlation with the temperature dependence of the KIE. Both the kinetic and dynamic phenomena can be modeled computationally. These results provide the first means of directly connecting temperature dependence of KIE's to dynamic motion in the active site in an enzyme‐catalyzed reaction.
This is from the Experimental Biology 2018 Meeting. There is no full text article associated with this published in The FASEB Journal.
Details
- Title: Subtitle
- Picosecond Active‐Site Dynamics Correlate with the Temperature Dependence of KIEs in Enzyme‐Catalyzed Hydride Transfer
- Creators
- Christopher M Cheatum - University of Iowa
- Resource Type
- Journal article
- Publication Details
- The FASEB journal, Vol.32(S1), pp.475.4-475.4
- Publisher
- The Federation of American Societies for Experimental Biology
- DOI
- 10.1096/fasebj.2018.32.1_supplement.475.4
- ISSN
- 0892-6638
- eISSN
- 1530-6860
- Number of pages
- 1
- Language
- English
- Date published
- 04/2018
- Academic Unit
- Liberal Arts and Science Admin; Chemistry
- Record Identifier
- 9984217443202771
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