Genomic insights into the biosynthesis and physiology of the cyanobacterial neurotoxin 3-N-methyl-2,3-diaminopropanoic acid (BMAA)

Maria De Quintanilha Mantas, Peter B Nunn, Geoffrey A Codd, Daniel Barker

Research output: Contribution to journalArticlepeer-review

Abstract

Cyanobacteria are an ancient clade of photosynthetic prokaryotes, present in many habitats throughout the world, including water resources. They can present health hazards to humans and animals due to the production of a wide range of toxins (cyanotoxins), including the diamino acid neurotoxin, β-N-methylaminoalanine (BMAA). Knowledge of the biosynthetic pathway for BMAA, and its role in cyanobacteria, is lacking. Present evidence suggests that BMAA is derived by 3-N methylation of 2,3-diaminopropanoic acid (2,3-DAP) and, although the latter has never been reported in cyanobacteria, there are multiple pathways to its biosynthesis known in other bacteria and in plants. Here, we used bioinformatics analyses to investigate hypotheses concerning 2,3-DAP and BMAA biosynthesis in cyanobacteria. We assessed the potential presence or absence of each enzyme in candidate biosynthetic routes known in Albizia julibrissin, Lathyrus sativus seedlings, Streptomyces, Clostridium, Staphylococcus aureus, Pantoea agglomerans, and Paenibacillus larvae, in 130cyanobacterial genomes using sequence alignment, profile hidden Markov models, substrate specificity/active site identification and the reconstruction of gene phylogenies. Most enzymes involved in pathways leading to 2,3-DAP in other species were not found in the cyanobacteria analysed. Nevertheless, two species appear to have the genes sbnA and sbnB, responsible for forming the 2,3-DAP constituent in staphyloferrin B, a siderophore from Staphylococcus aureus. It is currently undetermined whether these species are also capable of biosynthesising BMAA. It is possible that, in some cyanobacteria, the formation of 2,3-DAPand/or BMAA is associated with environmental iron-scavenging. The pam gene cluster, responsible for the biosynthesis of the BMAA-containing peptide, paenilamicin, so far appears to be restricted to Paenibacillus larvae. It was not detected in any of the cyanobacterial genomes analysed, nor was it found in 93 other Paenibacillus genomes or in the genomes of two BMAA-producing diatom species. We hypothesise that the presence, in some cyanobacterial species, of the enzymes 2,3-diaminopropionate ammonia-lyase(DAPAL) and reactive intermediate deaminase A (RidA) may explain the failure to detect2,3-DAP in analytical studies. Overall, the taxonomic distribution of 2,3-DAP and BMAA in cyanobacteria is unclear; there may be multiple and additional routes, and roles, for the biosynthesis of 2,3-DAP and BMAA in these organisms.
Original languageEnglish
Article number112953
Number of pages14
JournalPhytochemistry
Volume200
Early online date18 Apr 2022
DOIs
Publication statusE-pub ahead of print - 18 Apr 2022

Keywords

  • cyanobacteria
  • toxin
  • cyanotoxin
  • biochemical pathways
  • 3-N-Methyl-2,3-diaminopropanoic acid (BMAA)
  • ,3-Diaminopropanoic acid (2,3-DAP)
  • siderophores
  • paenilamicins
  • bioinformatics
  • genomes

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