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Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Enzyme dynamics during catalysis measured by NMR spectroscopy
Dorothee Kern1, Elan Z Eisenmesser, Magnus Wolf-Watz
1Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454, USA.
Methods in Enzymology
|April 6, 2005
Summary
Enzyme dynamics in the microsecond-to-millisecond timescale are crucial for biological processes. These conformational changes, revealed by advanced NMR techniques, are intrinsic and may limit enzyme catalysis rates.
Area of Science:
- Biochemistry
- Biophysics
- Enzymology
Background:
- Enzyme catalysis involves dynamic processes often occurring in the microsecond to millisecond timescale.
- While static enzyme structures are well-studied, enzyme dynamics during catalysis remain largely unknown.
- Understanding these dynamics is key to comprehending enzyme function and efficiency.
Purpose of the Study:
- To investigate enzyme dynamics during the catalytic cycle using advanced Nuclear Magnetic Resonance (NMR) techniques.
- To explore the role of conformational flexibility in enzyme function and catalysis.
- To determine if enzyme dynamics are rate-limiting for catalytic turnover.
Main Methods:
- Application of dynamic NMR methods including ZZ-exchange, line-shape analysis, Carr-Purcell-Meiboom-Gill (CPMG), and rotating frame spin-lattice relaxation (R(1rho)) experiments.
- These methods detect conformational rearrangements with interconversion rates between 0.1 and 10(5) s(-1).
- Studies were performed on enzymes in free states, complex with ligands, and during catalysis.
Main Results:
- Demonstrated the first application of dynamic NMR methods to enzymes during catalysis.
- Revealed that microsecond-to-millisecond timescale flexibility is an intrinsic property of enzymes.
- Quantitative analysis showed large-scale collective motions in enzymes.
- Observed frequencies of motion comparable to enzyme turnover rates.
Conclusions:
- Enzyme flexibility in the microsecond to millisecond time regime is essential for their function.
- Conformational rearrangements may be rate-limiting for catalysis in several enzymes.
- Dynamic NMR methods provide critical insights into the catalytic cycle of enzymes.
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