Translation elongation factor-3 (EF-3): an evolving eukaryotic ribosomal protein?

Area of Science:

• Molecular Biology
• Mycology
• Biochemistry

Background:

• Fungi possess a unique requirement for a third soluble translation elongation factor, elongation factor 3 (EF-3).
• EF-3 exhibits ribosome-dependent ATPase and GTPase activities crucial for in vivo translation elongation.
• The gene encoding EF-3 (YEF3) has been identified in various fungal species.

Purpose of the Study:

• To investigate the functional domains and evolutionary significance of fungal elongation factor 3 (EF-3).
• To elucidate the role of EF-3 in fungal protein synthesis accuracy and ribosomal function.

Main Methods:

• Computer-assisted analysis of Saccharomyces cerevisiae EF-3 amino acid sequence.
• Identification of conserved functional domains and similarities to other protein families (ABC, myosin, ribosomal proteins).
• Comparative analysis of EF-3 homologues across fungal species and Chlorella virus CVK2.

Main Results:

• Identified two ATP binding/catalytic domains, an amino-terminal region similar to E. coli S5 ribosomal protein, and predicted rRNA, tRNA, and mRNA interaction sites.
• Discovered amino acid similarity to myosin proteins, suggesting a role in motive force.
• Confirmed conservation of functional regions among fungal EF-3 proteins and a viral homologue.

Conclusions:

• EF-3 may optimize fungal protein synthesis accuracy by modulating ribosomal conformation and activity.
• EF-3 represents an evolving ribosomal protein with intrinsic ATPase activities, analogous to higher eukaryotes.
• EF-3 provides insights into the evolutionary divergence of fungi from other eukaryotic lineages.