PDBsum entry 6rvb

Oxidoreductase

PDB id: 6rvb

Contents

Protein chains

443 a.a.

Ligands

FAD ×4

NAD ×4

COA ×4

Waters ×112

PDB id:

6rvb

Name:

Oxidoreductase

Title:

Nadh-dependent coenzyme a disulfide reductase soaked with nadh

Structure:

Nadh oxidase. Chain: a, b, c, d. Engineered: yes

Source:

Thermus thermophilus. Organism_taxid: 274. Gene: tt_c1484. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.90Å R-factor: 0.202 R-free: 0.246

Authors:

J.Koepke,J.Preu

Key ref:

A.M.Lencina et al. (2019). Characterization and X-ray structure of the NADH-dependent coenzyme A disulfide reductase from Thermus thermophilus. Biochim Biophys Acta Bioenerg, 1860, 148080. PubMed id: 31520616 DOI: 10.1016/j.bbabio.2019.148080

Date:

31-May-19 Release date: 25-Sep-19

Protein chains

Q72HK3  (Q72HK3_THET2) -  NADH oxidase from Thermus thermophilus (strain ATCC BAA-163 / DSM 7039 / HB27)

Seq: 443 a.a.

Struc: 443 a.a.

Enzyme reactions

• Enzyme class: E.C.1.6.-.-

DOI no: 10.1016/j.bbabio.2019.148080

Biochim Biophys Acta Bioenerg 1860:148080 (2019)

PubMed id: 31520616

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

A.M.Lencina, J.Koepke, J.Preu, C.Muenke, R.B.Gennis, H.Michel, L.A.Schurig-Briccio.

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.