The Membrane‐Bound Nitrate Reductase A from Escherichia Coli: Nar GHI

Abstract

The bacterium Escherichia coli is able to survive in a wide range of adverse environmental conditions. When oxygen is limited and nitrate is present, E. coli synthesizes a specific electron transfer chain to produce energy for its own survival. The chain is constituted by two membrane‐bound enzymes: the initial formate dehydrogenase FdnGHI and the terminal nitrate reductase NarGHI. Electrons are transferred from the formate oxidation site to the nitrate reduction site with a net translocation of protons across the cytoplasmic membrane. In the recent years, crystallographic studies have shed light on the structure and function of the two enzymes revealing a clear picture of the nitrate electron transfer chain at the atomic level. The present article focuses on the advances obtained on NarGHI, its function and architecture, and the eight redox cofactors that form like an electrical wire through all the enzymes, starting from the electron acceptor site to the catalytic center.