Exploring the mode of action of ebselen in Trypanosoma brucei hexokinase inhibition.
Int J Parasitol Drugs Drug Resist
; 3: 154-60, 2013 Dec.
Article
en En
| MEDLINE
| ID: mdl-24533305
Glycolysis is essential to Trypanosoma brucei, the causative agent of African sleeping sickness, suggesting enzymes in the pathway could be targets for drug development. Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one, EbSe) was identified in a screen as a potent inhibitor of T. brucei hexokinase 1 (TbHK1), the first enzyme in the pathway. EbSe has a history of promiscuity as an enzyme inhibitor, inactivating proteins through seleno-sulfide conjugation with Cys residues. Indeed, dilution of TbHK1 and inhibitor following incubation did not temper inhibition suggesting conjugate formation. Using mass spectrometry to analyze EbSe-based modifications revealed that two Cys residues (C327 and C369) were oxidized after treatment. Site-directed mutagenesis of C327 led to enzyme inactivation indicating that C327 was essential for catalysis. C369 was not essential, suggesting that EbSe inhibition of TbHK1 was the consequence of modification of C327 via thiol oxidation. Additionally, neither EbSe treatment nor mutation of the nine TbHK1 Cys residues appreciably altered enzyme quaternary structure.
BSF, bloodstream form; EbS, 2-phenyl-12-benzisothiazol-3(2H)-one; EbSe, ebselen (2-phenyl-12-benzisoselenazol-3(2H)-one); Ebselen; G6-P, glucose-6-phosphate; G6PDH, glucose-6-phosphate dehydrogenase; GK, glycerol kinase; Gly3P, glycerol-3-phosphate; HK, hexokinase; Hexokinase; Inhibitors; PF, procyclic form; TbHK, T. brucei hexokinase; Trypanosoma brucei; rTbHK1, recombinant Trypanosoma brucei hexokinase 1
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Int J Parasitol Drugs Drug Resist
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos