Biology subjects

Duerfeldt, A. S.

Publications and source records attributed to Duerfeldt, A. S..

2 recordsLinked to original sources

bioRxiv2022

Structure-Uptake Relationship Studies of Oxazolidinones in Gram-negative ESKAPE Pathogens

To date, little is known about applicability and/or generality of molecular features and how they impact small molecule permeation into Gram-negative bacteria. Identifying motifs or structural trends that correlate with broad and/or species-specific permeation would enable the rational design of new antibacterials. The clinical success of linezolid for treating Gram-positive infections paired with the high conservation of bacterial ribosomes predicts that if oxazolidinones were engineered to accumulate in Gram-negative bacteria, then this pharmacological class would find broad utility in eradicating infections. Here we report an investigative study of a strategically designed library of oxazolidinones to determine the effects of molecular structure on accumulation and biological activity. E. coli, A. baumannii, and P. aeruginosa strains with varying degrees of compromise (in efflux and outer membrane) were used to identify motifs that hinder permeation across the outer-membrane and/or enhance efflux susceptibility broadly and specifically between species. The results of this study illustrate that small changes in molecular structure are enough to overcome the efflux and/or permeation issues of this scaffold. Three oxazolidinone analogs (3e, 12f, and 14) were identified from this study that exhibit activity against all three pathogens assessed, a biological profile not observed for linezolid.

microbiology↗

bioRxiv2021

Loss of ClpP Function in Clostridioides difficile 630 Significantly Impacts Sporulation Systems

The Gram-positive bacterium Clostridioides difficile is a primary cause of hospital-acquired diarrhea, threatening both immunocompromised and healthy individuals. An important aspect of elucidating mechanisms that drive C. difficile persistence and virulence relies on developing a more complete understanding of sporulation. C. difficile sporulation is the single determinant of transmission and complicates treatment and prevention due to the chemical and physical resilience of spores. Hence, the identification of potentially druggable targets that significantly attenuate sporulation is important. In this report, we describe the impact of the loss of caseinolytic protease P (ClpP) isoforms in C. difficile strain 630 on sporulation phenotypes. Using CRISPR-Cas9 nickase mediated genome editing, stop codons were inserted early in the coding sequence for clpP1 and clpP2 to generate C. difficile mutants that no longer produced ClpP1 or ClpP2. The data show that these genetic modifications lead to altered sporulation phenotypes, germination efficiencies, and cytotoxicity. Comparative proteome profiling of C. difficile 630 WT and clpP mutants reveals potential proteolytic targets of ClpP that are involved in sporulation. These analyses further reveal the potential for preferred co-chaperone interactions for each ClpP isoform. Taken together, our results demonstrate that ClpP, a promising target in other Gram-positive pathogens, holds promise as an anti-sporulation target in C. difficile.

microbiology↗