Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.30.2 (
endonuclease
)
18,621
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The beneficial human gut bacterium
Akkermansia muciniphila
provides metabolites to other members of the gut microbiota by breaking down host mucin, but most of its other metabolic functions have not been investigated.
A. muciniphila
strain Muc
T
is known to use cobamides, the vitamin B
12
family of cofactors with structural diversity in the lower ligand. However,
A. muciniphila
Muc
T
is unable to synthesize cobamides
de novo
, and the specific forms that can be used by
A. muciniphila
have not been examined. We found that the levels of growth of
A. muciniphila
Muc
T
were nearly identical with each of seven cobamides tested, in contrast to nearly all bacteria that had been studied previously. Unexpectedly, this promiscuity is due to cobamide remodeling-the removal and replacement of the lower ligand-despite the absence of the canonical remodeling enzyme
CbiZ
in
A. muciniphila
We identified a novel enzyme, CbiR, that is capable of initiating the remodeling process by hydrolyzing the phosphoribosyl bond in the nucleotide loop of cobamides. CbiR does not share similarity with other cobamide remodeling enzymes or B
12
-binding domains and is instead a member of the apurinic/apyrimidinic (AP)
endonuclease
2 enzyme superfamily. We speculate that CbiR enables bacteria to repurpose cobamides that they cannot otherwise use in order to grow under cobamide-requiring conditions; this function was confirmed by heterologous expression of
cbiR
in
Escherichia coli
Homologs of CbiR are found in over 200 microbial taxa across 22 phyla, suggesting that many bacteria may use CbiR to gain access to the diverse cobamides present in their environment.
IMPORTANCE
Cobamides, comprising the vitamin B
12
family of cobalt-containing cofactors, are required for metabolism in all domains of life, including most bacteria. Cobamides have structural variability in the lower ligand, and selectivity for particular cobamides has been observed in most organisms studied to date. Here, we discovered that the beneficial human gut bacterium
Akkermansia muciniphila
can use a diverse range of cobamides due to its ability to change the cobamide structure via a process termed cobamide remodeling. We identify and characterize the novel enzyme CbiR that is necessary for initiating the cobamide remodeling process. The discovery of this enzyme has implications for understanding the ecological role of
A. muciniphila
in the gut and the functions of other bacteria that produce this enzyme.
...
PMID:Identification of a Novel Cobamide Remodeling Enzyme in the Beneficial Human Gut Bacterium Akkermansia muciniphila. 3329 80
