Identification of Electron Transfer in the System of Ferredoxins and Ferredoxin Reductases from Mycolicibacterium smegmatis

Abstract

Steroid-26-monooxygenases belong to the cytochrome P450 superfamily and function as part of three-component systems together with ferredoxins and ferredoxin reductases providing electron transport. The P450-dependent redox partners of the actinobacterial strain Mycolicibacterium smegmatis mc2155 were investigated. The genes encoding mycolibacterial ferredoxins (FdxD and FdxE) and ferredoxin reductases (FdrA and FprA) were overexpressed in E. coli cells. A scheme for isolation and purification of synthesized recombinant proteins using affinity chromatography was developed, resulting in electrophoretically homogeneous preparations. Spectral analysis of ferredoxin reductase showed absorption peaks characteristic of FAD-containing proteins. The reaction of cytochrome c reduction using recombinant proteins was carried out, demonstrating that FdxD, FdxE, FdrA, and FprA can act as components of electron transport from the reducing equivalents of NAD(P)H.