Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design

Journal of Lipid Research

Wenxu Zhou¹  Boden H. Vanderloop¹  W. David Nes¹  Crista D. Thomas¹  Emilio Ramos¹  Medhanie E. Kidane¹  Minu Chaudhuri²  Ujjal Singha² 

[1] Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409;Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208;

关键词: phytosterol biosynthesis;    sterol C24-methyltransferase;    ergosterol biosynthesis inhibitors;    Acanthamoeba;    anti-amoeba drugs;   

DOI  :  

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown