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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Pepsin homologues in bacteria
Neil D Rawlings1, Alex Bateman
1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK. ndr@sanger.ac.uk
BMC Genomics
|September 18, 2009
Summary
Pepsin family A1 proteases are found in bacteria, not just eukaryotes. Bacterial pepsin homologues are intracellular and suggest ancient gene duplication predating bacteria-eukaryote divergence.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Genomics
Background:
- Peptidase family A1, including pepsin, was thought to be exclusive to eukaryotes.
- Pepsin's bilobed structure suggests ancient gene duplication and fusion.
- Retropepsin (family A2) shares structural similarity but requires dimerization for activity.
Purpose of the Study:
- To investigate the evolutionary origins of the pepsin family.
- To explore the presence of pepsin homologues in prokaryotes.
- To gain insights into the evolution of peptidase family A1.
Main Methods:
- Comparative genomics analysis of completed bacterial and archaeal genomes.
- Sequence similarity searches for pepsin homologues.
- Phylogenetic analysis of identified homologues.
Main Results:
- Pepsin homologues were identified in seven bacterial species but not in archaea.
- Bacterial homologues lack signal peptides, indicating intracellular function at neutral pH.
- Bacterial homologues possess a Thr218 to Asp substitution, conferring neutral pH activity.
Conclusions:
- Peptidase family A1 is present in both bacteria and eukaryotes.
- Bacterial homologues suggest an ancient duplication and fusion event predating eukaryotic-bacterial divergence.
- Bacterial pepsin homologues provide crucial evolutionary insights into this enzyme family.
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