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The relationship of protein conservation and sequence length
David J Lipman1, Alexander Souvorov, Eugene V Koonin
1National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20894, USA. lipman@ncbi.nlm.nih.gov
BMC Evolutionary Biology
|November 2, 2002
Summary
Protein length varies with function, but evolutionary forces also shape protein sequences. Studies reveal shorter proteins evolve when specific functional constraints are absent, impacting protein conservation across species.
Area of Science:
- Evolutionary biology
- Molecular biology
- Bioinformatics
Background:
- Protein sequence length is generally dictated by function.
- Organismal protein length diversity reflects varied functional roles.
- Studying proteins under weaker constraints may reveal additional evolutionary forces on length.
Purpose of the Study:
- To investigate the relationship between protein conservation and sequence length.
- To identify evolutionary trends affecting protein length distributions.
- To compare length distributions across different organisms and conservation levels.
Main Methods:
- Performed sequence comparisons across diverse organisms (E. coli, A. fulgidus, S. cerevisiae, D. melanogaster, H. sapiens).
- Distinguished between highly conserved and poorly conserved proteins.
- Analyzed protein length distributions for conserved and nonconserved groups.
Main Results:
- Conserved and nonconserved proteins exhibit distinct length distributions across all studied organisms.
- Conserved proteins are generally longer than poorly conserved proteins.
- Poorly conserved proteins show narrower length peaks, approximating minimal lengths for structural folds in prokaryotes.
Conclusions:
- A clear relationship exists between protein conservation and sequence length.
- Evolutionary trends favor shorter proteins when specific functional constraints are relaxed.
- Findings suggest evolutionary pressures beyond direct functional requirements influence protein length.