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Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues
Published on: July 14, 2015
New insight into long-range nonadditivity within protein double-mutant cycles
Andrei Y Istomin1, M Michael Gromiha, Oleg K Vorov
1Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina 28223, USA.
Proteins
|September 7, 2007
Summary
In proteins, mutations in distant residues are nonadditive if they belong to the same rigid cluster. This finding offers new insights into protein stability and design, challenging previous assumptions about mutation effects.
Area of Science:
- Biophysics
- Biochemistry
- Structural Biology
Background:
- Additivity principles are widely used in chemistry and biology but often fail in complex biomacromolecules.
- Nonadditivity in protein double mutant cycles is understood for close residues but poorly described for long distances.
Purpose of the Study:
- To test the hypothesis that long-range mutational effects in proteins are nonadditive between residues in the same rigid cluster and additive between residues in different clusters.
- To provide a robust description of long-range nonadditivity in protein double mutant cycles.
Main Methods:
- Analysis of protein double mutant free energy cycles.
- Statistical evaluation of mutational effects based on residue clustering within the wild type protein structure.
Main Results:
- A statistically significant hypothesis was found: mutational effects are nonadditive for spatially separated residues within the same rigid cluster (P-values 10^-5 to 10^-6).
- This study demonstrates the first statistically significant evidence for long-range nonadditivity in proteins.
- Nonadditivity is not limited to contacting residues, extending over large distances within protein structures.
Conclusions:
- Long-range nonadditivity in protein double mutant cycles is linked to residues belonging to the same rigid structural cluster.
- These findings enhance the understanding of protein stability, structure-function relationships, and protein design.
- The results challenge conventional views and provide a new framework for analyzing complex biomacromolecular interactions.
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