Protein Family Models

Cytochrome c oxidase (E.C:7.1.1.9) is a key enzyme in aerobic metabolism. Proton pumping haem-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes. The CuB-haem a3 (or haem o) binuclear centre, associated with the largest subunit I of cytochrome c and ubiquinol oxidases (E.C:1.10.3.11), is directly involved in the coupling between dioxygen reduction and proton pumping [1,2,3,4]. Some terminal oxidases generate a transmembrane proton gradient across the plasma membrane (prokaryotes) or the mitochondrial inner membrane (eukaryotes). The enzyme complex consists of 3-4 subunits (prokaryotes) up to 13 polypeptides (mammals) of which only the catalytic subunit (equivalent to mammalian subunit I (COXI) is found in all haem-copper respiratory oxidases. The presence of a bimetallic centre (formed by a high-spin haem and copper B) as well as a low-spin haem, both ligated to six conserved histidine residues near the outer side of four transmembrane spans within CO I is common to all family members [2,3]. [1]. 8638158. The whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A. Tsukihara T, Aoyama H, Yamashita E, Tomizaki T, Yamaguchi H, Shinzawa-Itoh K, Nakashima R, Yaono R, Yoshikawa S;. Science 1996;272:1136-1144. [2]. 8013452. Evolution of cytochrome oxidase, an enzyme older than atmospheric oxygen. Castresana J, Lubben M, Saraste M, Higgins DG;. EMBO J. 1994;13:2516-2525. [3]. 31489376. Dimeric structures of quinol-dependent nitric oxide reductases (qNORs) revealed by cryo-electron microscopy. Gopalasingam CC, Johnson RM, Chiduza GN, Tosha T, Yamamot. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16

Gene:

cyoB

Date:

2021-10-28

cytochrome ubiquinol oxidase subunit I is a heme-copper oxygen reductase, located in the mitochondrial inner membrane or the bacterial inner cell membrane, which catalyzes the reduction of molecular oxygen to water and is typically the terminal electron ac

Date:

2016-05-13

Cytochrome o terminal oxidase complex is the component of the aerobic respiratory chain which reacts with oxygen, reducing it to water with the concomitant transport of 4 protons across the membrane. Also known as the cytochrome bo complex, cytochrome o ubiquinol oxidase contains four subunits, two heme b cofactors and a copper atom which is believed to be the oxygen active site. This complex is structurally related to the cytochrome caa3 oxidases which utilize cytochrome c as the reductant and contain heme a cofactors, as well as the intermediate form aa3 oxidases which also react directly with quinones as the reductant.

Gene:

cyoB

Date:

2024-02-27