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Cellular origin of the viral capsid-like bacterial microcompartments
Mart Krupovic1, Eugene V Koonin2
1Department of Microbiology, Institut Pasteur, 25 rue du Dr. Roux, 75015, Paris, France. krupovic@pasteur.fr.
Biology Direct
|November 15, 2017
Summary
Bacterial microcompartments (BMC) share structural similarities with viral capsids but have unknown origins. Research suggests BMC shell proteins evolved from cellular proteins, supporting the hypothesis of protein recruitment in viral evolution.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Bacterial microcompartments (BMC) are protein shells enclosing enzymes, resembling viral capsids.
- BMC shell proteins (BMC-H and BMC-P) are functionally analogous to viral capsid proteins.
- The evolutionary origins of BMC proteins remain enigmatic due to lack of structural similarity to known capsid proteins.
Purpose of the Study:
- To investigate the evolutionary origins of Bacterial microcompartment shell proteins.
- To determine if BMC proteins were exapted from existing cellular proteins.
Main Methods:
- Comparative analysis of protein structures.
- Sequence comparison of BMC shell proteins (BMC-H and BMC-P) with cellular proteins.
Main Results:
- BMC-H protein shows likely exaptation from PII signaling protein.
- BMC-P protein shows likely exaptation from OB-fold domain-containing protein.
- Structural and sequence data support the exaptation of BMC proteins from cellular proteomes.
Conclusions:
- The origins of Bacterial microcompartments are likely rooted in the repurposing of cellular proteins.
- This finding supports the broader hypothesis that viral structural proteins can be recruited from cellular proteomes.
- BMC protein evolution provides insights into the emergence of complex cellular organelles.
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