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Characterization and X-ray structure of the NADH-dependent coenzyme A disulfide reductase from Thermus thermophilus

DOI: 10.1016/j.bbabio.2019.148080 DOI Help

Authors: Andrea M. Lencina (University of Illinois) , Juergen Koepke (Max Planck Institute of Biophysics) , Julia Preu (Max Planck Institute of Biophysics) , Conny Muenke (Max Planck Institute of Biophysics) , Robert B. Gennis (University of Illinois) , Hartmut Michel (Max Planck Institute of Biophysics) , Lici A. Schurig-briccio (University of Illinois)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochimica Et Biophysica Acta (bba) - Bioenergetics

State: Published (Approved)
Published: September 2019

Abstract: The crystal structure of the enzyme previously characterized as a type-2 NADH:menaquinone oxidoreductase (NDH-2) from Thermus thermophilus has been solved at a resolution of 2.9 Å and revealed that this protein is, in fact, a coenzyme A-disulfide reductase (CoADR). Coenzyme A (CoASH) replaces glutathione as the major low molecular weight thiol in Thermus thermophilus and is maintained in the reduced state by this enzyme (CoADR). Although the enzyme does exhibit NADH:menadione oxidoreductase activity expected for NDH-2 enzymes, the specific activity with CoAD as an electron acceptor is about 5-fold higher than with menadione. Furthermore, the crystal structure contains coenzyme A covalently linked Cys44, a catalytic intermediate (Cys44-S-S-CoA) reduced by NADH via the FAD cofactor. Soaking the crystals with menadione shows that menadione can bind to a site near the redox active FAD, consistent with the observed NADH:menadione oxidoreductase activity. CoADRs from other species were also examined and shown to have measurable NADH:menadione oxidoreductase activity. Although a common feature of this family of enzymes, no biological relevance is proposed. The CoADR from T. thermophilus is a soluble homodimeric enzyme. Expression of the recombinant TtCoADR at high levels in E. coli results in a small fraction that co-purifies with the membrane fraction, which was used previously to isolate the enzyme wrongly identified as a membrane-bound NDH-2. It is concluded that T. thermophilus does not contain an authentic NDH-2 component in its aerobic respiratory chain.

Journal Keywords: Coenzyme A disulfide reductase; NADH oxidation; X-ray structure; Flavoprotein; Thermus thermophilus

Subject Areas: Biology and Bio-materials

Instruments: I03-Macromolecular Crystallography

Other Facilities: ESRF

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