Structural evolution of an amphibian-specific globin: A computational evolutionary biochemistry approach

Area of Science:

• Evolutionary biology
• Molecular evolution
• Structural bioinformatics

Background:

• The globin gene family offers insights into protein evolution.
• A novel amphibian-specific globin A (GbA) arose from an alpha-globin precursor in Pelobatoidea and Neobatrachia.
• GbA in Rana catesbeiana is monomeric, unlike the ancestral alpha-globin homodimeric state.

Purpose of the Study:

• Investigate the genetic and physical mechanisms behind the origin of new protein properties.
• Determine the prevalence of the loss of the homodimeric state within the GbA clade.
• Characterize GbA gene loci in Bufo bufo.

Main Methods:

• Computational molecular evolution analyses.
• Structural bioinformatics.
• Gene locus characterization in Bufonidae species.

Main Results:

• Identified two GbA clades in Neobatrachia.
• Observed GbA deletion in Ranidae, but retention and expansion in Bufonidae.
• Found pervasive loss of the ancestral homodimeric state across the GbA clade.

Conclusions:

• Loss of GbA oligomerization is linked to amino acid substitutions in Pelobatoidea and independent deletions in Neobatrachia.
• Further taxonomic sampling is needed to ascertain the ancestral GbA oligomeric state.
• Independent genetic events led to the loss of homodimerization in different GbA lineages.