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Multi‐Targeted Inhibition of an Essential Bacterial Enzyme
Author(s) -
Soares da Costa Tatiana P.,
Gardi Chamodi K.,
Christoff Rebecca,
Sutton J. Mark,
Abbott Belinda M.,
Perugini Matthew A.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.810.3
Subject(s) - allosteric regulation , biochemistry , active site , enzyme , bacteria , escherichia coli , druggability , biology , lysine , peptidoglycan , pseudomonas aeruginosa , chemistry , amino acid , gene , genetics
The cell wall of Gram‐negative bacteria consists of peptidoglycan chains linked together by oligopeptidic sequences comprised of the amino acids L ‐Ala, D ‐Ala, D ‐Glu and meso‐ diaminopimelate (DAP). Meso ‐DAP is synthesized via the DAP pathway that also yields the basic amino acid, L ‐lysine. Gene knock‐out studies show that enzymes functioning in the DAP pathway are essential to bacteria, including dihydrodipicolinate synthase (DHDPS). DHDPS is an allosteric enzyme that catalyzes the first‐committed and rate‐limiting step in DAP biosynthesis. It forms a homo‐tetrameric structure that gives rise to at least two ‘druggable’ sites, namely (a) the active site and (b) the allosteric site, which binds lysine to mediate a feedback inhibition response. Given its essentiality to bacteria and absence in humans, DHDPS represents a valid but as yet unchartered target for antimicrobial development. Recently, we have developed two classes of small molecule inhibitors that target the DHDPS active site and allosteric site using a contemporary multi‐disciplinary workflow spanning biophysics, biochemistry, medicinal chemistry, microbiology and structural biology. Inhibition studies in combination with biophysical techniques have demonstrated that these compounds are broad‐spectrum inhibitors of bacterial DHDPS in vitro , representing the most potent DHDPS inhibitors discovered to date. Using viability and time‐kill assays, these inhibitors have been shown to be bactericidal against both drug‐sensitive and drug‐resistant strains of Gram‐negative bacteria (MIC = 8 – 64 μg/ml), including Acinetobacter baumannii , Pseudomonas aeruginosa and Escherichia coli , but were non‐toxic against cultured human cells at >1024 μg/ml. Importantly, these compounds have been shown to synergize with FDA‐approved classes of antibiotics, including β‐lactams, fluoroquinolones, rifampicin and aminoglycosides. This study illustrates the potential for DHDPS inhibitors to be developed into a new class of antimicrobials with excellent potential to be combined with current antibiotics to yield innovative multi‐targeted formulations to minimize the emergence of resistance. Support or Funding Information Australian National and Health Medical Research Council (NHMRC)and CASS Foundation This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .