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A Simple and Inexpensive Method for Determining Cold Sensitivity and Adaptation in Mice
Published on: March 17, 2015
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Dynamic allostery can drive cold adaptation in enzymes.
Harry G Saavedra1,2, James O Wrabl1,2, Jeremy A Anderson1,2
1Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
Nature
|June 8, 2018
Summary
Organisms adapt to new environments through evolutionary changes in enzymes. This study reveals how distant mutations allosterically tune enzyme activity, impacting substrate affinity and turnover rates without altering the active site structure.
Area of Science:
- Evolutionary biology
- Biochemistry
- Enzyme kinetics
Background:
- Organisms adapt to environmental niches, such as temperature extremes, through evolutionary changes.
- Enzyme orthologues from different environments show adaptive mutations that maintain catalytic rates.
- Adaptive mutations often occur at surface sites, distant from the enzyme's active site, posing a question about allosteric regulation.
Purpose of the Study:
- To investigate the role of enzyme dynamics in allosteric regulation and adaptation.
- To explore how distal sequence changes modulate enzyme activity.
- To understand the mechanism by which enzymes fine-tune function during evolution.
Main Methods:
- Engineering entropy-tuning mutations into distal sites of Escherichia coli adenylate kinase.
- Quantitatively assessing the impact of these mutations on enzyme dynamics, substrate affinity, and turnover rates.
- Analyzing the spatial separation of control over key enzymatic parameters.
Main Results:
- A dynamics-based allosteric tuning mechanism was revealed.
- Fluctuations in the LID domain control substrate affinity.
- Dynamic attenuation in the AMP-binding domain influences enzyme turnover.
- A spatial separation in the control of enzymatic parameters was uncovered.
Conclusions:
- Enzyme adaptation can be achieved through dynamics-based allosteric regulation, altering function without changing the ground-state structure.
- This mechanism offers a new model for understanding the relationship between enzyme dynamics and turnover.
- Dynamics-based regulation represents a potentially widespread evolutionary strategy for fine-tuning biological function.
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