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. Author manuscript; available in PMC: 2022 Jul 24.
Published in final edited form as: J Med Chem. 2021 May 11;64(10):6608–6620. doi: 10.1021/acs.jmedchem.0c01926

Fig. 5. T. vaginalis TrxR isoform expression and inhibition by gold(I) complexes.

Fig. 5.

A. Dendrogram of amino acid sequence alignments of the five T. vaginalis TrxR isoforms, with TrxR of G. lamblia as a root. Blue numbers refer to percentage amino acid identity of the respective isoform relative to TrxRc (100%). B. Expression levels of the five TrxR isoforms were analyzed by qPCR in two metronidazole-sensitive (MzS) lines of T. vaginalis (green bars) and two metronidazole-resistant (MzR) lines (orange bars). TrxR levels are expressed relative to GAPDH and represent mean + SEM of four independent experiments. C. Coomassie Blue-stained SDS-PAGE gel of E. coli BL21extracts before (−) and after (+) IPTG induction of recombinant TrxRh2, and after Ni-NTA affinity purification of this TrxR isoform (h2) and purified recombinant rTrxRc (c). D. In vitro inhibitory activities (pIC50) of a library of gold(I) complexes against the two indicated recombinant TrxR isoforms. E. Correlation of in vitro inhibitory activity (pIC50) of gold(I) complexes against the two most abundant recombinant TrxR isoforms (red, TrxRc; blue, TrxRh2) and total TrxR in whole-cell extracts of T.vaginalis F1623. F. Correlation of TrxR inhibition (pIC50) in whole-cell extracts and trichomonacidal activity (pEC50) of gold(I) complexes. In panels D-F, each dot represents one gold(I) complex (mean, n=3 experiments). Pearson correlation coefficients (R2) and their significances (p value) were calculated, and regression lines are shown. In F, correlation was only calculated for the compounds with good trichomonacidal activity (pEC50>5) and a pEC50/pIC50 ratio of ≤1 (black dots), while compounds with low trichomonacidal activity (gray dots below gray line) and compounds with pEC50/pIC50 ratios >1 (circled dots with compound names) were not considered for this purpose. The latter are likely to act by mechanisms other than TrxR inhibition. The diagonal dashed line in F represents a unit slope with pEC50:pIC50 ratios of one.