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The 'evolvability' of promiscuous protein functions
Amir Aharoni1, Leonid Gaidukov, Olga Khersonsky
1Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
Nature Genetics
|November 30, 2004
Summary
Protein evolution for new functions, like drug resistance, is rapid. Mutations initially boost new traits without harming essential functions, enabling adaptation before gene duplication.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Molecular Biology
Background:
- The rapid evolution of protein functions, such as antibiotic resistance or chemical degradation, remains poorly understood.
- This adaptive process relies on phenotypic plasticity induced by mutations, yet mutations can negatively impact essential survival functions.
Purpose of the Study:
- To elucidate the mechanisms by which proteins acquire new functions rapidly without compromising essential ones at the single-protein level.
- To understand how conflicting evolutionary demands are resolved during protein adaptation.
Main Methods:
- Directed laboratory evolution experiments were employed to observe protein adaptation in real-time.
- Analysis focused on the effects of mutations on both native and promiscuous protein functions.
Main Results:
- The evolution of new functions is initiated by mutations that minimally affect the protein's original function.
- These key mutations significantly enhance latent or promiscuous functions, providing an initial fitness advantage.
- This allows proteins to gain new capabilities without immediate loss of essential roles.
Conclusions:
- Proteins adapt to new functions by first exploiting and enhancing existing, albeit minor, promiscuous activities.
- This strategy permits adaptation without compromising vital functions, paving the way for subsequent evolutionary steps like gene duplication.