Characterisation of the highly conserved CutRS two-component system in Streptomyces spp.

Mclean, Thomas (2021) Characterisation of the highly conserved CutRS two-component system in Streptomyces spp. Doctoral thesis, University of East Anglia.

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Abstract

Streptomyces spp. are filamentous Actinobacteria with the propensity to produce a
wide range of specialised metabolites. Many of our current therapeutics originate
from these bacteria but their effectiveness is dwindling due to antimicrobial
resistance. The biosynthesis of specialised metabolites by streptomycetes is
intimately linked to the extracellular environment, detected through stimulusresponse
mechanisms such as two-component systems (TCS). These systems consist
of a membrane-bound sensor kinase (SK) and partner DNA-binding response
regulator (RR), and they enable detection of, and response to, a multitude of signals.
Previously to this work we identified 15 highly conserved TCS in the genus
Streptomyces, including the first TCS ever described in Streptomyces spp., CutRS.
During this work, I characterised CutRS in S. venezuelae and S. coelicolor using a
combination of classical microbiology and cutting-edge molecular techniques.
Deletion of the cutRS genes results in a distinct developmental phenotype in S.
venezuelae and the overproduction of specialised metabolites in both species. Using
a combination of ChIP-seq, ReDCaT SPR and quantitative proteomics I demonstrate
that CutR regulates the expression of two serine protease encoding genes, htrB and
htrA3, and hypothesise that this is in response to secretion stress. Investigation into
the SK CutS reveals an unusual extracellular dual cysteine-containing sensory domain
which we propose is key to a novel mechanism of signal detection. Furthermore, I
describe the development of a novel SPR-based technique which we anticipate will
vastly increase the discovery of SK ligands in vitro. Overall, this work demonstrates a
novel mechanism of TCS signal detection and further expands our understanding of
these complex signalling systems and with this we can begin to imitate and subvert
these systems for our own benefit. Ultimately, we hope this work enables the
discovery of new antimicrobials to combat the threat of global antimicrobial
resistance.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Jackie Webb
Date Deposited: 29 Apr 2022 12:32
Last Modified: 29 Apr 2022 12:32
URI: https://ueaeprints.uea.ac.uk/id/eprint/84858
DOI:

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