A possible aquatic origin of the Thiaminase TenA of the human gut symbiont Bacteroides thetaiotaomicron

Régis Stentz, Jitender Cheema, Mark Philo, Simon R. Carding

Research output: Contribution to journalArticlepeer-review

Abstract

TenA thiamin-degrading enzymes are commonly found in prokaryotes, plants, fungi and algae and are involved in the thiamin salvage pathway. The gut symbiont Bacteroides thetaiotaomicron (Bt) produces a TenA protein (BtTenA) which is packaged into its extracellular vesicles. An alignment of BtTenA protein sequence with proteins from different databases using the basic local alignment search tool (BLAST) and the generation of a phylogenetic tree revealed that BtTenA is related to TenA-like proteins not only found in a small number of intestinal bacterial species but also in some aquatic bacteria, aquatic invertebrates, and freshwater fish. This is, to our knowledge, the first report describing the presence of TenA-encoding genes in the genome of members of the animal kingdom. By searching metagenomic databases of diverse host-associated microbial communities, we found that BtTenA homologues were mostly represented in biofilms present on the surface of macroalgae found in Australian coral reefs. We also confirmed the ability of a recombinant BtTenA to degrade thiamin. Our study shows that BttenA-like genes which encode a novel sub-class of TenA proteins are sparingly distributed across two kingdoms of life, a feature of accessory genes known for their ability to spread between species through horizontal gene transfer.

Original languageEnglish
Pages (from-to)482-491
Number of pages10
JournalJournal of Molecular Evolution
Volume91
Issue number4
Early online date6 Apr 2023
DOIs
Publication statusPublished - Aug 2023

Keywords

  • Bacterial extracellular vesicles
  • Horizontal gene transfer
  • Monophyletic group
  • Thiamin

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