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:3.5.1.1 (
asparaginase
)
2,695
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Salmonella enterica
serovar Typhimurium is the only organism demonstrated to utilize fructose-asparagine (F-Asn) as a source of carbon and nitrogen. In this report, we first used a bioinformatics approach to identify other microorganisms that encode homologs of the
Salmonella
F-Asn utilization enzymes FraB (deglycase), FraD (kinase), and FraE (
asparaginase
). These candidate organisms were then tested with up to four different methods to confirm their ability to utilize F-Asn. The easiest and most broadly applicable method utilized a biological toxicity assay, which is based on the observation that F-Asn is toxic to a
Salmonella fraB
mutant. Candidate organisms were grown in a rich medium containing F-Asn, and depletion of F-Asn from the medium was inferred by the growth of a
Salmonella fraB
mutant in that same medium. For select organisms, the toxicity assay was cross-validated by direct mass spectrometry-aided measurement of F-Asn in the spent-culture media and through demonstration of FraB and FraD enzyme activity in cellular extracts. For prototrophs, F-Asn utilization was additionally confirmed by growth in a minimal medium containing F-Asn as the sole carbon source. Collectively, these studies established that
Clostridium
bolteae
,
Clostridium acetobutylicum
, and
Clostridium clostridioforme
can utilize F-Asn, but
Clostridium difficile
cannot;
Klebsiella oxytoca
and some
Klebsiella pneumoniae
subspecies can utilize F-Asn; and some
Citrobacter rodentium
and
Citrobacter freundii
strains can also utilize F-Asn. Within
Salmonella enterica
, the host-adapted serovars Typhi and Paratyphi A have lost the ability to utilize F-Asn.
IMPORTANCE
Fructose
-asparagine (F-Asn) is a precursor to acrylamide that is found in human foods, and it is also a nutrient source for
Salmonella enterica
, a foodborne pathogen. Here, we determined that among the normal intestinal microbiota, there are species of
Clostridium
that encode the enzymes required for F-Asn utilization. Using complementary experimental approaches, we have confirmed that three members of
Clostridium
, two members of
Klebsiella
, and two members of
Citrobacter
can indeed utilize F-Asn. The
Clostridium
spp. likely compete with
Salmonella
for F-Asn in the gut and contribute to competitive exclusion. FraB, one of the enzymes in the F-Asn utilization pathway, is a potential drug target because inhibition of this enzyme leads to the accumulation of a toxic metabolite that inhibits the growth of
Salmonella
species. This study identifies the potential off-target organisms that need to be considered when developing therapeutics directed at FraB.
...
PMID:Identification of Bacterial Species That Can Utilize Fructose-Asparagine. 2926 89
