The evolution of respiratory chain complex I from smaller functional modules
NADH:quinone oxidoreductase, or complex I, is a large membrane bound enzyme in the respiratory chain of living organisms, that has evolved from the combination of smaller functional building blocks. The enzyme has a conserved core structure, comprising 14 protein subunits: Seven subunits protrude from the membrane and contain a flavin and eight iron-sulfur clusters. The remaining seven subunits in
