Small
Molecule Inhibitors of the BfrB–Bfd Interaction
Decrease <i>Pseudomonas aeruginosa</i> Fitness and Potentiate
Fluoroquinolone Activity
Achala
N. D. Punchi Hewage
Huili Yao
Baskar Nammalwar
Krishna Kumar Gnanasekaran
Scott Lovell
Richard A. Bunce
Kate Eshelman
Sahishna M. Phaniraj
Molly M. Lee
Blake R. Peterson
Kevin P. Battaile
Allen B. Reitz
Mario Rivera
10.1021/jacs.9b00394.s001
https://acs.figshare.com/articles/journal_contribution/Small_Molecule_Inhibitors_of_the_BfrB_Bfd_Interaction_Decrease_i_Pseudomonas_aeruginosa_i_Fitness_and_Potentiate_Fluoroquinolone_Activity/8101160
The iron storage
protein bacterioferritin (BfrB) is central to
bacterial iron homeostasis. The mobilization of iron from BfrB, which
requires binding by a cognate ferredoxin (Bfd), is essential to the
regulation of cytosolic iron levels in <i>P. aeruginosa</i>. This paper describes the structure-guided development of small
molecule inhibitors of the BfrB–Bfd protein–protein
interaction. The process was initiated by screening a fragment library
and followed by obtaining the structure of a fragment hit bound to
BfrB. The structural insights were used to develop a series of 4-(benzylamino)-
and 4-((3-phenylpropyl)amino)-isoindoline-1,3-dione analogs that selectively
bind BfrB at the Bfd binding site. Challenging <i>P. aeruginosa</i> cells with the 4-substituted isoindoline analogs revealed a dose-dependent
growth phenotype. Further investigation determined that the analogs
elicit a pyoverdin hyperproduction phenotype that is consistent with
blockade of the BfrB–Bfd interaction and ensuing irreversible
accumulation of iron in BfrB, with concomitant depletion of iron in
the cytosol. The irreversible accumulation of iron in BfrB prompted
by the 4-substituted isoindoline analogs was confirmed by visualization
of BfrB-iron in <i>P. aeruginosa</i> cell lysates separated
on native PAGE gels and stained for iron with Ferene S. Challenging <i>P. aeruginosa</i> cultures with a combination of commercial
fluoroquinolone and our isoindoline analogs results in significantly
lower cell survival relative to treatment with either antibiotic or
analog alone. Collectively, these findings furnish proof of concept
for the usefulness of small molecule probes designed to dysregulate
bacterial iron homeostasis by targeting a protein–protein interaction
pivotal for iron storage in the bacterial cell.
2019-04-30 00:00:00
Bfd binding site
aeruginosa cell lysates
isoindoline analogs results
cytosolic iron levels
iron homeostasis
isoindoline analogs
Potentiate Fluoroquinolone Activity
BfrB
pyoverdin hyperproduction phenotype
dose-dependent growth phenotype
Small Molecule Inhibitors
iron storage protein bacterioferritin