Structural Enzymology of Hydroxylation Reactions on Aromatic Compounds

In the next funding period we want to continue our studies on the mechanism of flavoenzymes in the aromatic degradation pathways. A.) We want to investigate the coupled electron transfer in multicomponent Rieske-type oxygenases. Two different types of NADH-dependent flavin-containing reductases are found in conjunction with Rieske-type oxygenases, which undergo redox dependent conformational changes to regulate electron transfer to an iron-sulphur cluster contained either in an extra domain or in an additional ferredoxin. We want to study the structural basis of the controlled electron transfer between the different partners. B.) Further, we could recently show that the flavoenzyme xenobiotic reductase A is involved in the degradation of quinoline. Xenobiotic reductase A belongs to a new flavoenzyme subfamily whose catalytic mechanism is only poorly understood. We want to study the function of several individual residues in the active site and want to compare it to the well-studied enzymes of the old-yellow-enzyme family.