Polyamine Biosynthesis and Function in Microbial Systems

Polyamines are small, positively charged molecules—most notably putrescine, spermidine and spermine—ubiquitous across bacterial, archaeal and viral systems. Their biosynthesis typically begins with the decarboxylation of amino acids such as ornithine or arginine to yield putrescine, followed by stepwise aminopropyl transfer reactions that generate higher polyamines. Alternative pathways exist in diverse bacteria, including carboxynorspermidine routes that employ fused aminotransferase–decarboxylase enzymes. In viruses, polyamine biosynthetic genes acquired from hosts enable direct manipulation of host metabolism to support viral replication. Functionally, polyamines stabilise nucleic acid structures, regulate translation and transcription, contribute to stress resilience and are essential for processes such as cell growth, biofilm formation and virulence. Recent advances in structural biology have revealed novel enzyme architectures and regulatory mechanisms that balance polyamine pools through both biosynthesis and acetylation‐mediated turnover. By influencing microbial physiology, pathogenicity and environmental interactions—from hospital‐acquired infections to oceanic carbon fixation—polyamines represent key targets for antimicrobial development and biotechnological exploitation.

Research from Nature Portfolio

Recent studies have identified a novel N-acetyltransferase, Dpa, in Acinetobacter baumannii that specifically modifies 1,3-diaminopropane, a species-specific polyamine. Structural analysis revealed that Dpa adopts a β-swapped quaternary arrangement distinct from other bacterial acetyltransferases but akin to eukaryotic counterparts. Functional assays demonstrated that Dpa activity directly influences bacterial motility and biofilm development by modulating the pool of unmodified 1,3-diaminopropane, highlighting a regulatory mechanism linking polyamine acetylation to virulence traits.

Research from all publishers

Investigations into the virosphere have uncovered a broad repertoire of virus‐encoded polyamine metabolic enzymes, including pyridoxal 5′-phosphate-dependent and pyruvoyl-dependent decarboxylases, spermidine synthases and N-acetyltransferases. These viral pathways enable both synthesis and sequestration of spermidine and its analogues, underpinning a global role for polyamines in phage and giant virus replication. In a parallel study, the structure and kinetics of the SpeG spermidine/spermine N-acetyltransferase from methicillin-resistant Staphylococcus aureus USA300 were elucidated, revealing a dynamic oligomeric state and allosteric regulation by polyamine substrates and acetyl‐coenzyme A. This work provides insight into enzyme specificity and cooperativity that govern intracellular polyamine homeostasis in a major human pathogen. Additionally, in the marine diatom Phaeodactylum tricornutum, co-overexpression of spermidine synthase and S-adenosylmethionine decarboxylase significantly elevated spermidine levels and accelerated growth, demonstrating the multifactorial regulation of polyamine biosynthesis and its potential to boost primary productivity in ecologically important microalgae.

Polyamine Biosynthesis and Function in Microbial Systems publication trend

The graph below shows the total number of articles in polyamine biosynthesis and function in microbial systems across all publications each year (not limited to Nature Index journals).

Technical terms

Polyamines: Small aliphatic polycations (e.g. putrescine, spermidine) that stabilise nucleic acids and modulate cellular processes.

Ornithine decarboxylase (ODC): Enzyme that removes a carboxyl group from ornithine to form putrescine in the initial step of many polyamine pathways.

Spermidine synthase: Enzyme that transfers an aminopropyl group to putrescine, producing spermidine.

Acetyltransferase: Enzyme transferring an acetyl group to polyamines, influencing their activity, localisation and export.

Biofilm: Structured microbial community embedded in a self-produced extracellular matrix that enhances survival and virulence.

References

1. A polyamine acetyltransferase regulates the motility and biofilm formation of Acinetobacter baumannii. Nature Communications (2023).
2. Functional polyamine metabolic enzymes and pathways encoded by the virosphere. Proceedings of the National Academy of Sciences of the United States of America (2023).
3. Structural and Kinetic Characterization of the SpeG Spermidine/Spermine N-acetyltransferase from Methicillin-Resistant Staphylococcus aureus USA300. Cells (2023).
4. Enhancing the Spermidine Synthase-Based Polyamine Biosynthetic Pathway to Boost Rapid Growth in Marine Diatom Phaeodactylum tricornutum. Biomolecules (2024).