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:2.7.13.3 (
histidine kinase
)
2,405
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We show that
Yersinia enterocolitica
strain Ye9 (bio-serotype 2/O:9) utilizes heme-containing molecules as an iron source. The Ye9 genome contains two multigenic clusters,
hemPRSTUV
-1 and
hemPRST
-2, encoding putative heme receptors HemR1 and HemR2, that share 62% amino acid identity. Expression of these proteins in an
Escherichia coli
mutant defective in heme biosynthesis allowed this strain to use hemin and hemoglobin as a source of porphyrin. The
hemPRSTUV
-1 and
hemPRST
-2 clusters are organized as operons, expressed from the p
hem-1
and weaker p
hem-2
promoters, respectively. Expression of both operons is negatively regulated by iron and the iron-responsive transcriptional repressor Fur. In addition, OmpR, the response regulator of two component system (TCSs)
EnvZ
/OmpR, represses transcription of both operons through interaction with binding sequences overlapping the -35 region of their promoters. Western blot analysis of the level of HemR1 in
ompR,
fur
, and
ompRfur
mutants, showed an additive effect of these mutations, indicating that OmpR may regulate HemR expression independently of Fur. However, the effect of OmpR on the activity of the p
hem-1
promoter and on HemR1 production was observed in both iron-depleted and iron-replete conditions, i.e., when Fur represses the iron-regulated promoter. In addition, a hairpin RNA thermometer, composed of four uracil residues (FourU) that pair with the ribosome-binding site in the 5'-untranslated region (5'-UTR) of
hemR1
was predicted by
in silico
analysis. However, thermoregulated expression of HemR1 could not be demonstrated. Taken together, these data suggest that Fur and OmpR control iron/heme acquisition via a complex mechanism based on negative regulation of
hemR1
and
hemR2
at the transcriptional level. This interplay could fine-tune the level of heme receptor proteins to allow
Y. enterocolitica
to fulfill its iron/heme requirements without over-accumulation, which might be important for pathogenic growth within human hosts.
...
PMID:OmpR-Mediated Transcriptional Regulation and Function of Two Heme Receptor Proteins of
Yersinia enterocolitica
Bio-Serotype 2/O:9. 3029 93
