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@ARTICLE{Krger:917136,
author = {Krüger, Aileen and Frunzke, Julia},
title = {{A} pseudokinase version of the histidine kinase {C}hr{S}
promotes high heme tolerance of {C}orynebacterium
glutamicum},
journal = {Frontiers in microbiology},
volume = {13},
issn = {1664-302X},
address = {Lausanne},
publisher = {Frontiers Media},
reportid = {FZJ-2023-00368},
pages = {997448},
year = {2022},
note = {Biotechnologie 1},
abstract = {Heme is an essential cofactor for almost all living cells
by acting as prosthetic group for various proteins or
serving as alternative iron source. However, elevated levels
are highly toxic for cells. Several corynebacterial species
employ two paralogous, heme-responsive two-component systems
(TCS), ChrSA and HrrSA, to cope with heme stress and to
maintain intracellular heme homeostasis. Significant
cross-talk at the level of phosphorylation between these
systems was previously demonstrated. In this study, we have
performed a laboratory evolution experiment to adapt
Corynebacterium glutamicum to increasing heme levels.
Isolated strains showed a highly increased tolerance to heme
growing at concentrations of up to 100 μM. The strain
featuring the highest heme tolerance harbored a frameshift
mutation in the catalytical and ATPase-domain (CA-domain) of
the chrS gene, converting it into a catalytically-inactive
pseudokinase $(ChrS_CA-fs).$ Reintroduction of the
respective mutation in the parental C. glutamicum strain
confirmed high heme tolerance and showed a drastic
upregulation of hrtBA encoding a heme export system,
conserved in Firmicutes and Actinobacteria. The strain
encoding the ChrS pseudokinase variant showed significantly
higher heme tolerance than a strain lacking chrS. Mutational
analysis revealed that induction of hrtBA in the evolved
strain is solely mediated via the cross-phosphorylation of
the response regulator (RR) ChrA by the kinase HrrS and
BACTH assays revealed the formation of heterodimers between
HrrS and ChrS. Overall, our results emphasize an important
role of the ChrS pseudokinase in high heme tolerance of the
evolved C. glutamicum and demonstrate the promiscuity in
heme-dependent signaling of the paralogous two-component
systems facilitating fast adaptation to changing
environmental conditions.},
cin = {IBG-1},
ddc = {570},
cid = {I:(DE-Juel1)IBG-1-20101118},
pnm = {2171 - Biological and environmental resources for
sustainable use (POF4-217)},
pid = {G:(DE-HGF)POF4-2171},
typ = {PUB:(DE-HGF)16},
pubmed = {36160252},
UT = {WOS:000859687500001},
doi = {10.3389/fmicb.2022.997448},
url = {https://juser.fz-juelich.de/record/917136},
}