Evolutionary adaptation of bacterial proteomes to translation-impeding sequences

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Microbial translation arrest peptides regulate gene expression by monitoring cellular environments.
• Previous research identified bacterial arrest peptides with C-terminal RAPP-like sequences upstream of protein localization genes.

Purpose of the Study:

• To investigate the evolutionary dynamics and regulatory roles of RAPP-like sequences in bacterial translation.
• To determine the specific RAPP and RGPP sequences that readily evolve into robust, EF-P-refractory translation-impeding sequences.

Main Methods:

• Comparative analysis of RAPP-like sequences across bacterial proteomes.
• Identification and characterization of RAPP/RGPP-containing arrest peptides in Streptomyces lividans.
• Assessment of translation arrest efficiency and EF-P resistance.

Main Results:

• RAPP (Arg-Ala-Pro-Pro) and RGPP (Arg-Gly-Pro-Pro) sequences show a strong propensity to evolve into robust translation arrest peptides, resistant to EF-P.
• RAPP-like motifs are generally excluded from bacterial proteomes, suggesting a risk to translation.
• These motifs are often found near the C-terminus of small secretory/membrane proteins and upstream of genes with diverse functions.

Conclusions:

• RAPP/RGPP sequences exhibit bidirectional evolutionary trends: exclusion from proteomes and adaptation as regulatory arrest peptides.
• These peptides, found upstream of various genes in Streptomyces lividans, highlight diverse regulatory roles beyond protein localization.
• The study reveals the complex interplay between protein sequence evolution, translation regulation, and gene function in bacteria.