Structures and Electron Transport Paths in the Four Families of Flavin-Based Electron Bifurcation Enzymes

Abstract

Oxidoreductases facilitating electron transfer between molecules are pivotal in metabolic pathways. Flavin-based electron bifurcation (FBEB), a recently discovered energy coupling mechanism in oxidoreductases, enables the reversible division of electron pairs into two acceptors, bridging exergonic and otherwise unfeasible endergonic reactions. This chapter explores the four distinct FBEB complex families and highlights a decade of structural insights into FBEB complexes. In this chapter, we discuss the architecture, electron transfer routes, and conformational changes across all FBEB families, revealing the structural foundation that facilitate these remarkable functions.

Keywords: Catalytic mechanism; Electron bifurcation; Electron transfer; Flavin; Iron-sulfur cluster; Structural biology; cryoEM.