6FWH

Acanthamoeba IGPD in complex with R-C348 to 1.7A resolution

Summary for 6FWH

• Entry DOI: 10.2210/pdb6fwh/pdb
• Descriptor: Imidazoleglycerol-phosphate dehydratase, MANGANESE (II) ION, [(2R)-2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propyl]phosphonic acid, ... (5 entities in total)
• Functional Keywords: inhibitor, histidine biosynthesis, acanthamoeba, lyase
• Biological source: Acanthamoeba castellanii (Amoeba)
• Total number of polymer chains: 12
• Total formula weight: 261065.30

Authors

Roberts, C.W.,Bisson, C.,Baker, P.J. (deposition date: 2018-03-06, release date: 2018-07-18, Last modification date: 2024-01-17)

Primary citation

Rice, C.A.,Campbell, S.J.,Bisson, C.,Owen, H.J.,Sedelnikova, S.E.,Baker, P.J.,Rice, D.W.,Henriquez, F.L.,Roberts, C.W.
Structural and functional studies of histidine biosynthesis in Acanthamoeba spp. demonstrates a novel molecular arrangement and target for antimicrobials.
PLoS ONE, 13:e0198827-e0198827, 2018

PubMed Abstract: Acanthamoeba is normally free-living, but sometimes facultative and occasionally opportunistic parasites. Current therapies are, by necessity, arduous and yet poorly effective due to their inabilities to kill cyst stages or in some cases to actually induce encystation. Acanthamoeba can therefore survive as cysts and cause disease recurrence. Herein, in pursuit of better therapies and to understand the biochemistry of this understudied organism, we characterize its histidine biosynthesis pathway and explore the potential of targeting this with antimicrobials. We demonstrate that Acanthamoeba is a histidine autotroph, but with the ability to scavenge preformed histidine. It is able to grow in defined media lacking this amino acid, but is inhibited by 3-amino-1,2,4-triazole (3AT) that targets Imidazoleglycerol-Phosphate Dehydratase (IGPD) the rate limiting step of histidine biosynthesis. The structure of Acanthamoeba IGPD has also been determined in complex with 2-hydroxy-3-(1,2,4-triazol-1-yl) propylphosphonate [(R)-C348], a recently described novel inhibitor of Arabidopsis thaliana IGPD. This compound inhibited the growth of four Acanthamoeba species, having a 50% inhibitory concentration (IC50) ranging from 250-526 nM. This effect could be ablated by the addition of 1 mM exogenous free histidine, but importantly not by physiological concentrations found in mammalian tissues. The ability of 3AT and (R)-C348 to restrict the growth of four strains of Acanthamoeba spp. including a recently isolated clinical strain, while not inducing encystment, demonstrates the potential therapeutic utility of targeting the histidine biosynthesis pathway in Acanthamoeba.

PubMed: 29969448
DOI: 10.1371/journal.pone.0198827

Experimental method

X-RAY DIFFRACTION (1.79 Å)