Molecular Characterization of an rsmD -Like rRNA Methyltransferase from the Wolbachia Endosymbiont of Brugia malayi and Antifilarial Activity of Specific Inhibitors of the Enzyme

Abstract

bThe endosymbiotic organism Wolbachia is an attractive antifilarial drug target. Here we report on the cloning and expression of an rsmD-like rRNA methyltransferase from the Wolbachia endosymbiont of Brugia malayi, its molecular properties, and assays for specific inhibitors. The gene was found to be expressed in all the major life stages of B. malayi. The purified enzyme expressed in Escherichia coli was found to be in monomer form in its native state. The activities of the specific inhibitors (heteroaryl compounds) against the enzyme were tested with B. malayi adult and microfilariae for 7 days in vitro at various concentrations, and NSC-659390 proved to be the most potent compound (50% inhibitory concentration [IC 50 ], 0.32 M), followed by NSC-658343 (IC 50 , 4.13 M) and NSC-657589 (IC 50 , 7.5 M). On intraperitoneal administration at 5 mg/kg of body weight for 7 days to adult jirds into which B. malayi had been transplanted intraperitoneally, all the compounds killed a significant proportion of the implanted worms. A very similar result was observed in infected mastomys when inhibitors were administered. Docking studies of enzyme and inhibitors and an in vitro tryptophan quenching experiment were also performed to understand the binding mode and affinity. The specific inhibitors of the enzyme showed a higher affinity for the catalytic site of the enzyme than the nonspecific inhibitors and were found to be potent enough to kill the worm (both adults and microfilariae) in vitro as well as in vivo in a matter of days at micromolar concentrations. The findings suggest that these compounds be evaluated against other pathogens possessing a methyltransferase with a DPPY motif and warrant the design and synthesis of more such inhibitors.

AtRsmD Is Required for Chloroplast Development and Chloroplast Function in Arabidopsis thaliana

“…Accordingly, homologous proteins of E. coli RsmD are present in higher plant chloroplasts ( Supplementary Figures 3 , 4 ) but are completely absent in both Archaea and Eukarya. The AtRsmD protein shares highly conserved motifs, such as Dx(F/G/Y)xGxG and (D/N/T)PP(F/Y), with those in E. coli ; these motifs are required for S-adenosyl-L-methionine (SAM) binding ( Supplementary Figure 3 ; Rana et al, 2013 ; Ngoc et al, 2021b ). Importantly, a recent report demonstrated that AtRsmD is a MTase responsible for chloroplast 16S rRNA m 2 G 915 methylation, which is absent in the atrsmd-1 mutant ( Ngoc et al, 2021b ).…”

Humans from Wuchereria bancrofti endemic area elicit substantial immune response to proteins of the filarial parasite Brugia malayi and its endosymbiont Wolbachia

“…The mosquitoes were fed on infected donor animals. On day 9 ± 1, infective larvae (L3) of B. malayi were recovered from fed mosquitoes by the Baermann method [15]. …”

Isatin thiazoles as antidiabetic: Synthesis, in vitro enzyme inhibitory activities, kinetics, and in silico studies

“…, 132 (30), and 104 (37). (CAS # 488746-10-7] [40] Solid; yield: 80%; M.P: 294-296°C; [43] Solid; yield: 85%; M.P: 278-282°C;…”

“…The synthetic library of isatin thiazole derivatives was evaluated for their α‐amylase and α‐glucosidase inhibitory activities and all compounds showed good to moderate results. The series consists of three intermediates ( 3a–c ) which are reported in the literature, [ 38–40 ] among the 27 derivatives ( 4–30 ), 15 compounds 5, 8, 9, 11–13, 18, 20, 21, 23, 24, 26, 27, 29 , and 30 are new; while 12 compounds 4, 6, 7, 10, 14–17, 19, 22, 25 , and 28 were previously reported in the literature [ 41–47 ] (Figure ).…”