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Species comparison of calmodulin sequences.
1Department of Biochemistry, Howard University College of Medicine, Washington, DC 20059.
Protein Sequences & Data Analysis
|September 1, 1990
Summary
Calmodulin shows high sequence conservation across vertebrates, particularly in key calcium-binding regions. These conserved residues are crucial for calmodulin
Area of Science:
- Biochemistry
- Molecular Biology
- Evolutionary Biology
Background:
- Calmodulin is a vital calcium-binding protein involved in numerous cellular processes.
- Previous studies indicated high sequence similarity in vertebrate calmodulin.
- Non-vertebrate calmodulin sequences exhibit greater variability.
Purpose of the Study:
- To identify conserved residues in calmodulin across different species.
- To pinpoint regions of calmodulin sequence identity essential for function.
- To understand the evolutionary constraints on calmodulin structure and function.
Main Methods:
- Comparative sequence analysis of calmodulin from various vertebrate and non-vertebrate species.
- Identification of invariant amino acid residues and conserved sequence blocks.
- Focus on Ca2+ binding loops and adjacent regions.
Main Results:
- Calmodulin sequences from human, rat, chicken, and toad show no amino acid substitutions.
- High sequence identity is observed in residues 27-53 (Ca2+ binding loop I and interloop region).
- Residues 100-129 (near Ca2+ binding loop III) and negatively charged side chains at 82-84 are also conserved.
Conclusions:
- Vertebrate calmodulin sequences are highly conserved, suggesting strong functional importance.
- Specific regions, including Ca2+ binding loops and the central alpha-helix, are under significant evolutionary constraint.
- These conserved residues likely play critical roles in calmodulin's interaction with target proteins.