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

cbb3-type cytochrome c oxidase subunit I (CcoN) is the catalytic subunit of cytochrome c oxidase, which is a component of the respiratory chain that catalyzes the reduction of oxygen to water

Date:

2017-07-07

This HMM represents the largest subunit, I, of the ccb3-type cytochrome c oxidase, with two protohemes and copper. It shows strong homology to subunits of other types of cytochrome oxidases. Species with this type, all from the Proteobacteria so far, include Neisseria meningitidis, Helicobacter pylori, Campylobacter jejuni, Rhodobacter sphaeroides, Rhizobium leguminosarum, and others. Gene symbols ccoN and fixN are synonymous.

Gene:

ccoN

Date:

2024-10-21