The redox state regulates the conformation of Rv2466c to activate the antitubercular prodrug TP053

DOI: 10.1074/jbc.M115.677039
PMID: 26546681

Authors: David Albesa-Jove (Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU)) , Natalia Comino (Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU)) , Montse Tersa (Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU)) , Elisabeth Mohorko (ETH Zurich) , Saioa Urresti (Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU)) , Elisa Dainese (University of Padova) , Laurent R. Chiarelli (University of Padova) , Maria Rosalia Pasca (University of Padova) , Riccardo Manganelli (University of Padova) , Vadim Makarov (A. N. Bakh Institute of Biochemistry, Russian Academy of Science) , Giovanna Riccardi (University of Pavia) , Dmitri I. Svergun (EMBL Hamburg) , Rudi Glockshuber (ETH Zurich) , Marcelo Guerin (Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry

State: Published (Approved)
Published: November 2015
Diamond Proposal Number(s): 8302 , 10130

Abstract: Rv2466c is a key oxidoreductase that mediates the reductive activation of TP053, a thienopyrimidine derivative that kills replicating and non-replicating Mycobacterium tuberculosis, but whose mode of action remains enigmatic. Rv2466c is a homodimer in which each subunit displays a modular architecture comprising a canonical thioredoxin fold with a Cys19-Pro20-Trp21-Cys22 motif, and an insertion consisting of a four α-helical bundle and a short α-helical hairpin. Strong evidence is provided for dramatic conformational changes during the Rv2466c redox cycle, which are essential for TP053 activity. Strikingly, a new crystal structure of the reduced form of Rv2466c revealed the binding of a C-terminal extension in α-helical conformation to a pocket next to the active site cysteine pair at the interface between the thioredoxin domain and the helical insertion domain. The ab initio low-resolution envelopes obtained from small angle X-ray scattering showed that the fully reduced form of Rv2466c adopts a ′closed′ compact conformation in solution, similar to that observed in the crystal structure. In contrast, the oxidized form of Rv2466c displays an ′open′ conformation, where tertiary structural changes in the α-helical subdomain suffice to account for the observed conformational transitions. Altogether our structural, biochemical and biophysical data strongly support a model in which the formation of the catalytic disulfide bond upon TP053 reduction triggers local structural changes that open the substrate binding site of Rv2466c allowing the release of the activated, reduced form of TP053. Our studies suggest that similar structural changes might have a functional role in other members of the thioredoxin-fold superfamily.

Journal Keywords: Conformational Change; Enzyme; Mycobacterium Tuberculosis; Oxidation-Reduction (Redox); Small-Angle X-Ray Scattering (SAXS); Thioredoxin; X-Ray Crystallography

Diamond Keywords: Tuberculosis (TB); Bacteria

Subject Areas: Biology and Bio-materials, Medicine, Chemistry


Instruments: I04-Macromolecular Crystallography

Other Facilities: P12 at EMBL, PETRA III, DESY; SOLEIL

Added On: 20/11/2015 14:34

Documents:
PIIS0021925820393054.pdf

Discipline Tags:

Pathogens Antibiotic Resistance Infectious Diseases Health & Wellbeing Biochemistry Chemistry Structural biology Biophysics Drug Discovery Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)