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Protein WISDOM: A Workbench for In silico De novo Design of BioMolecules
Published on: July 25, 2013
Rapid sequence divergence in mammalian beta-defensins by adaptive evolution.
A I Maxwell1, G M Morrison, J R Dorin
1MRC Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, UK.
Novel beta-defensin genes were identified in mice and humans, revealing rapid evolution in antimicrobial peptide regions. One new gene, Defr1, shows unique structure and activity, impacting host defense understanding.
Area of Science:
- Genomics
- Evolutionary Biology
- Immunology
Background:
- Beta-defensin genes encode antimicrobial peptides crucial for host defense.
- These genes are clustered on human and mouse chromosome 8.
- Understanding their evolution and function is key to host-pathogen interactions.
Purpose of the Study:
- To identify and characterize novel beta-defensin genes in mice and humans.
- To investigate the evolutionary dynamics of beta-defensin gene clusters.
- To functionally analyze a newly identified beta-defensin-related gene (Defr1).
Main Methods:
- Hidden Markov models for novel gene identification.
- Transcript analysis to confirm gene expression.
- Comparative genomics and evolutionary analysis.
- Biochemical characterization of the Defr1 peptide.
Main Results:
- Identification of novel mouse and human beta-defensin genes with expressed transcripts.
- Evolutionary analysis indicates rapid divergence in mature peptide-encoding regions driven by positive selection.
- Characterization of Defr1, a novel beta-defensin-related gene with a unique structure and dual antimicrobial/chemotactic activity.
- Defr1's antimicrobial activity is salt-dependent against some bacteria but not *P. aeruginosa*.
Conclusions:
- Beta-defensin gene evolution is characterized by duplication and positive selection, particularly in the mature peptide domain, supporting adaptation against pathogens.
- Defr1 represents a divergent member of the beta-defensin family with implications for understanding host defense mechanisms.
- The findings highlight the structural and functional diversity within beta-defensins and their adaptive evolution.
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