Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design
Ergosterol biosynthesis pathways essential to pathogenic protozoa growth and absent from the human host offer new chokepoint targets. Here, we present characterization and cell-based interference of Acanthamoeba spp sterol 24-/28-methylases (SMTs) that catalyze the committed step in C28- and C29-ste...
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doaj-c5dd241f6f744dcebd1bd6c2550491672021-04-29T04:36:47ZengElsevierJournal of Lipid Research0022-22752017-12-01581223102323Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug designMedhanie E. Kidane0Boden H. Vanderloop1Wenxu Zhou2Crista D. Thomas3Emilio Ramos4Ujjal Singha5Minu Chaudhuri6W. David Nes7Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409; To whom correspondence should be addressed. e-mail:Ergosterol biosynthesis pathways essential to pathogenic protozoa growth and absent from the human host offer new chokepoint targets. Here, we present characterization and cell-based interference of Acanthamoeba spp sterol 24-/28-methylases (SMTs) that catalyze the committed step in C28- and C29-sterol synthesis. Intriguingly, our kinetic analyses suggest that 24-SMT prefers plant cycloartenol whereas 28-SMT prefers 24(28)-methylene lophenol in similar fashion to the substrate preferences of land plant SMT1 and SMT2. Transition state analog-24(R,S),25-epiminolanosterol (EL) and suicide substrate 26,27-dehydrolanosterol (DHL) differentially inhibited trophozoite growth with IC50 values of 7 nM and 6 µM, respectively, and EL yielded 20-fold higher activity than reference drug voriconazole. Against either SMT assayed with native substrate, EL exhibited tight binding ∼Ki 9 nM. Alternatively, DHL is methylated at C26 by 24-SMT that thereby, generates intermediates that complex and inactivate the enzyme, whereas DHL is not productively bound to 28-SMT. Steroidal inhibitors had no effect on human epithelial kidney cell growth or cholesterol biosynthesis at minimum amoebicidal concentrations. We hypothesize the selective inhibition of Acanthamoeba by steroidal inhibitors representing distinct chemotypes may be an efficient strategy for the development of promising compounds to combat amoeba diseases.http://www.sciencedirect.com/science/article/pii/S0022227520335574phytosterol biosynthesissterol C24-methyltransferaseergosterol biosynthesis inhibitorsAcanthamoebaanti-amoeba drugs |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Medhanie E. Kidane Boden H. Vanderloop Wenxu Zhou Crista D. Thomas Emilio Ramos Ujjal Singha Minu Chaudhuri W. David Nes |
spellingShingle |
Medhanie E. Kidane Boden H. Vanderloop Wenxu Zhou Crista D. Thomas Emilio Ramos Ujjal Singha Minu Chaudhuri W. David Nes Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design Journal of Lipid Research phytosterol biosynthesis sterol C24-methyltransferase ergosterol biosynthesis inhibitors Acanthamoeba anti-amoeba drugs |
author_facet |
Medhanie E. Kidane Boden H. Vanderloop Wenxu Zhou Crista D. Thomas Emilio Ramos Ujjal Singha Minu Chaudhuri W. David Nes |
author_sort |
Medhanie E. Kidane |
title |
Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
title_short |
Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
title_full |
Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
title_fullStr |
Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
title_full_unstemmed |
Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
title_sort |
sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design |
publisher |
Elsevier |
series |
Journal of Lipid Research |
issn |
0022-2275 |
publishDate |
2017-12-01 |
description |
Ergosterol biosynthesis pathways essential to pathogenic protozoa growth and absent from the human host offer new chokepoint targets. Here, we present characterization and cell-based interference of Acanthamoeba spp sterol 24-/28-methylases (SMTs) that catalyze the committed step in C28- and C29-sterol synthesis. Intriguingly, our kinetic analyses suggest that 24-SMT prefers plant cycloartenol whereas 28-SMT prefers 24(28)-methylene lophenol in similar fashion to the substrate preferences of land plant SMT1 and SMT2. Transition state analog-24(R,S),25-epiminolanosterol (EL) and suicide substrate 26,27-dehydrolanosterol (DHL) differentially inhibited trophozoite growth with IC50 values of 7 nM and 6 µM, respectively, and EL yielded 20-fold higher activity than reference drug voriconazole. Against either SMT assayed with native substrate, EL exhibited tight binding ∼Ki 9 nM. Alternatively, DHL is methylated at C26 by 24-SMT that thereby, generates intermediates that complex and inactivate the enzyme, whereas DHL is not productively bound to 28-SMT. Steroidal inhibitors had no effect on human epithelial kidney cell growth or cholesterol biosynthesis at minimum amoebicidal concentrations. We hypothesize the selective inhibition of Acanthamoeba by steroidal inhibitors representing distinct chemotypes may be an efficient strategy for the development of promising compounds to combat amoeba diseases. |
topic |
phytosterol biosynthesis sterol C24-methyltransferase ergosterol biosynthesis inhibitors Acanthamoeba anti-amoeba drugs |
url |
http://www.sciencedirect.com/science/article/pii/S0022227520335574 |
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