Hormone fatty acid modifications: gram negative bacteria and vertebrates demonstrate common structure and function.

Area of Science:

• Microbiology
• Endocrinology
• Biochemistry

Background:

• Quorum sensing (QS) regulates bacterial processes using autoinducers like acyl homoserine lactones (AHLs) in Gram-negative bacteria.
• Growth hormone (GH) release in vertebrates is stimulated by growth hormone secretagogues (GHSs), including the acylated peptide ghrelin.
• Ghrelin's activity depends on n-octanoylation at serine-3 (Ser3), a unique fatty acid modification in peptide hormones.

Purpose of the Study:

• To investigate the functional and structural similarities between bacterial QS signaling and vertebrate GH regulation.
• To explore the convergent evolution and biological significance of the conserved serine-acylated motif in AHLs and ghrelin.

Main Methods:

• Comparative analysis of molecular structures of N-acyl homoserine lactones (AHLs) and ghrelin.
• Hypothesizing functional parallels in food-seeking behaviors between Gram-negative bacteria and vertebrates.

Main Results:

• Identified N-Octanoyl-DL-homoserine lactone (C8-HL) as a representative bacterial autoinducer.
• Highlighted the structural homology between AHLs and ghrelin, specifically the conserved serine-acylated group.
• Proposed a functional similarity in food acquisition strategies between these diverse organisms.

Conclusions:

• The conserved serine-acylated motif in AHLs and ghrelin suggests convergent evolution.
• This structural similarity points to a shared, fundamental biological role in resource acquisition across different kingdoms.
• Understanding this conserved motif offers insights into evolutionary biology and signaling mechanisms.