Elucidation of Electron Transfer Pathways During Oxidative Protein Folding in Escherichia Coli

8 3.1. Catalysis of oxidative protein folding 8 3.2 De novo formation of disulfide bonds in E. coli: the discovery of DsbA 9 3.3. DsbA is the most oxidizing disulfide catalyst 11 3.4. DsbB provides the periplasm with oxidizing power 15 3.5. Correcting wrong disulfide bonds in the periplasm: disulfide bond isomerization by DsbC 18 3.6. DsbD provides reducing equivalents in a highly oxidizing environment 23 3.7. Dsb proteins and cytochrome c maturation 23 3.8. Disulfide bond formation does not interfere with disulfide isomerization 24 31 4.1. DsbB links electron transport and oxidative protein folding 31 4.1.1. In vitro reconstitution of a disulfide catalytic machine 31 4.1.2. Purification and identification of the DsbB activating factor 34 4.1.3. Both E. coli terminal oxidases reactivate DsbB 38 4.1.4. Reconstitution of the disulfide catalytic machine with purified cytochrome bo and bd oxidases 40 4.1.5. Ubiquinone acts as an electron acceptor during DsbB reoxidation 41 4.1.6. Components of the disulfide catalytic system 43 4.1.7. Disulfide oxidation under anaerobic conditions 44 4.2. DsbB is a novel quinone reductase 47 4.2.1. Demonstration of a novel enzymatic activity: ubiquinone dependent disulfide bond formation 47 4.2.2. DsbB contains bound coenzyme Q-8 (ubiquinone-40) after purification 50 4.2.3. Reconstitution of the entire oxidative protein folding pathway in vitro 53 4.3. Turning a disulfide isomerase into an oxidase 58 4.3.