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Evolution of enzymes in metabolism: a network perspective
Rui Alves1, Raphael A G Chaleil, Michael J E Sternberg
1Department of Biological Sciences, Structural Bioinformatics Group, Biochemistry Building, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK.
Journal of Molecular Biology
|July 4, 2002
Summary
Enzymes in metabolic pathways evolve locally within functional blocks of similar chemistry. This network-based study reveals homologous enzymes are more likely to evolve from nearby network neighbors, minimizing physiological disruption.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Systems Biology
Background:
- Existing models for enzyme evolution (retro-evolution, recruitment) are limited by study scale and pathway definitions.
- These models propose enzymes evolve from pathway ends or recruit templates from similar enzymes in other pathways.
Purpose of the Study:
- To investigate enzyme evolution in metabolic networks using a genome-wide network approach.
- To overcome limitations of previous studies by removing artificial pathway constraints and increasing scale.
Main Methods:
- Utilized a network approach to analyze enzyme evolution across fully sequenced genomes.
- Examined the proximity of homologous enzyme pairs within the metabolic reaction network.
Main Results:
- Homologous enzyme pairs are approximately twice as likely to evolve from enzymes within three steps in the reaction network compared to non-homologous pairs.
- Evidence suggests the conservation of catalyzed chemical reaction types among evolutionarily related enzymes.
Conclusions:
- Functional blocks of enzymes with similar chemistry appear to evolve within metabolic networks.
- Local evolution of enzymes likely causes fewer global physiological disruptions than evolution from distant network neighbors.