Download MendeleyStructural and Mechanistic Insights Into Type II Trypanosomatid Tryparedoxin-Dependent Peroxidases.
Alphey, M.S., Konig, J., Fairlamb, A.H.(2008) Biochem J 414: 375
- PubMed: 18522537 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1042/BJ20080889
- Primary Citation Related Structures:
2VUP - PubMed Abstract:
TbTDPX (Trypanosoma brucei tryparedoxin-dependent peroxidase) is a genetically validated drug target in the fight against African sleeping sickness. Despite its similarity to members of the GPX (glutathione peroxidase) family, TbTDPX2 is functional as a monomer, lacks a selenocysteine residue and relies instead on peroxidatic and resolving cysteine residues for catalysis and uses tryparedoxin rather than glutathione as electron donor. Kinetic studies indicate a saturable Ping Pong mechanism, unlike selenium-dependent GPXs, which display infinite K(m) and V(max) values. The structure of the reduced enzyme at 2.1 A (0.21 nm) resolution reveals that the catalytic thiol groups are widely separated [19 A (0.19 nm)] and thus unable to form a disulphide bond without a large conformational change in the secondary-structure architecture, as reported for certain plant GPXs. A model of the oxidized enzyme structure is presented and the implications for small-molecule inhibition are discussed.
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.
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