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The constraints protein-protein interactions place on sequence divergence
1MRC Laboratory of Molecular Biology, Hills Road, CB2 2QH, Cambridge, UK. sat@mrc-lmb.cam.ac.uk
Journal of Molecular Biology
|November 26, 2002
Summary
Protein interactions impose additional sequence constraints. Proteins in stable complexes show higher sequence identity between species than those without interactions, indicating evolutionary pressure.
Area of Science:
- Molecular Biology
- Evolutionary Biology
- Bioinformatics
Background:
- Residues in protein interfaces, ligand-binding sites, and active sites are generally more conserved than average amino acids.
- This raises the question of whether protein interactions impose unique evolutionary constraints beyond general functional restrictions.
Purpose of the Study:
- To investigate if protein interactions impose additional constraints on protein sequence divergence.
- To compare sequence divergence in proteins involved in stable complexes, transient interactions, and no known interactions.
Main Methods:
- Utilized sequence identities between Saccharomyces cerevisiae (SC) and Schizosaccharomyces pombe (SP) orthologues as a measure of sequence divergence.
- Categorized SC proteins into those in stable complexes, transient interactions, and non-interacting proteins.
Main Results:
- Protein interactions significantly influence sequence divergence, with distributions differing across interaction categories.
- Proteins in stable complexes exhibit higher average sequence identity (46%) compared to non-interacting proteins (38%).
- Proteins with transient interactions show intermediate sequence identity (41%).
Conclusions:
- Protein interactions, particularly stable ones, impose additional evolutionary constraints on sequence divergence.
- These constraints are evident across different functional categories and protein essentiality.