Related Experiment Video
Updated: May 24, 2026
07:49
Creating and Applying a Reference to Facilitate the Discussion and Classification of Proteins in a Diverse Group
Published on: August 16, 2017
Evolutionary origin of β-defensins
1Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, 100101 Beijing, China. Zhusy@ioz.ac.cn
Developmental and Comparative Immunology
|February 29, 2012
Summary
The evolutionary origin of vertebrate beta-defensins (antimicrobial peptides) was investigated by comparing them to invertebrate big defensins. Structural and genomic similarities suggest beta-defensins evolved from ancestral big defensins.
Area of Science:
- Evolutionary biology
- Immunology
- Biochemistry
Background:
- Beta-defensins are vertebrate-specific antimicrobial peptides (AMPs) crucial for innate immunity.
- Despite their conservation, the evolutionary origins of beta-defensins remain unclear.
Purpose of the Study:
- To investigate the evolutionary relationship between vertebrate beta-defensins and invertebrate big defensins.
- To elucidate the ancestral origins of beta-defensin molecules.
Main Methods:
- Comparative analysis of 3D structures of beta-defensins and big defensins.
- Examination of genomic organization of both peptide families.
- Phylogenetic analysis of big defensin distribution.
Main Results:
- Beta-defensins and the carboxyl-terminal domain of big defensins share conserved 3D structure and disulfide bridge patterns.
- A conserved single exon and upstream intron in genomic organization suggest a shared evolutionary origin.
- Big defensins are found across diverse invertebrate phyla, indicating an ancient origin of the beta-defensin domain.
Conclusions:
- Vertebrate beta-defensins likely evolved from ancestral big defensins via exon shuffling or intronization.
- The beta-defensin domain has ancient origins, traceable to the common ancestor of bilateral metazoans.
Related Concept Videos
01:16Transduction
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
02:26Conservation of Protein Domains Over Different Proteins
Protein domains are small structurally independent units that are part of a single amino acid chain. Although these domains are often structurally independent, they may rely on synergistic effects to perform their functions as part of a larger protein. Protein domains may be conserved within the same organism, as well as across different organisms.
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to form...
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to form...
01:08Evolution of Microbial Genome
Microbial genome evolution is a highly dynamic process shaped by continual gene gain and loss across species and strains. This genomic flexibility allows microorganisms to adapt rapidly to environmental pressures and interactions with other organisms. Central to understanding this diversity is the distinction between the core and pan genomes.The core genome comprises the genes shared by all sampled strains of a species, representing essential functions needed for fundamental cellular processes.
01:49Conserved Binding Sites
Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...