Mechanistic and structural diversity between cytochrome <i>bd</i> isoforms of <i>Escherichia coli</i>
Tamara N. Grund, Melanie Radloff, Di Wu, Hojjat Ghasemi Goojani, Luca F. Witte, Wiebke Jösting, Sabine Buschmann, Hannelore Müller, Isam Elamri, Sonja Welsch, Harald Schwalbe, Hartmut Michel, Dirk Bald, Schara Safarian
Abstract
Significance Bacterial aerobic respiration is a metabolic pathway that can adapt to changing environmental conditions. Most bacteria encode for two general types of terminal respiratory oxygen reductases that catalyze the reduction of molecular oxygen to water: heme-copper oxidases (HCO) and cytochrome bd- type oxidases. While HCO-type enzymes are conserved throughout all domains of life, cytochrome bd oxidases are present solely in prokaryotes. Due to their high oxygen affinity and insensitivity toward a wide range of naturally occurring HCO inhibitors, cytochrome bd oxidases confer bacteria with the ability to maintain aerobic respiration under hostile conditions, especially low-oxygen environments. The importance of cytochrome bd as a survival factor supports a key role for this enzyme as a drug target for combating infectious diseases.