Towards the Characterization of Putative Degradation Targets of Klebsiella pneumoniae Lon Protease by Quantitative Proteomics and in vitro Degradation Assays



Morgenroth-Rebin, Jarod

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University of Guelph


Klebsiella pneumoniae is an opportunistic bacterial pathogen, possessing numerous virulence factors to adapt to harsh host environments. Lon is an ATP-dependent serine protease in K. pneumoniae and was recently discovered to have a potential role in iron homeostasis. To identify potential targets of Lon impacting iron-homeostasis, this study used quantitative proteomics to identify proteins with significantly increased or decreased abundance binding to Nickel-Nitriloacetic acid agarose in the presence or absence of hexahistidine-tagged Lon. Candidate target proteins were purified and tested against Lon in vitro for degradation. Our results identified further links between Lon and iron-related proteins, while also uncovering a strong connection between Lon and sulfur metabolism/amino acid synthesis proteins in the Cys family. Overall, this work begins to test the potential interactions between Lon and proteins involved in iron homeostasis and uncovers a potential new role for Lon in sulfur homeostasis.



Klebsiella pneumoniae, Proteomics, Lon protease, Protease