Protein Family Models

This is the N-terminal region of the E or R chain, Ubiquitinol-cytochrome C reductase Fe-S subunit, of the hetero-hexameric cytochrome bc1 complex. This region is a TAT-signal region. The cytochrome bc1 complex is an oligomeric membrane protein complex that is a component of respiratory and photosynthetic electron transfer chains. The enzyme couples the transfer of electrons from ubiquinol to cytochrome c with the the generation of a protein gradient across the membrane [1]. The motif is also associated with Rieske (Pfam:PF00355), UCR_TM (Pfam:PF02921) and Ubiq-Cytc-red_N (Pfam:PF09165). [1]. 10873857. Structure at 2.3 A resolution of the cytochrome bc(1) complex from the yeast Saccharomyces cerevisiae co-crystallized with an antibody Fv fragment. Hunte C, Koepke J, Lange C, Rossmanith T, Michel H;. Structure. 2000;8:669-684. (from Pfam)

Date:

2024-10-16

The rieske domain has a [2Fe-2S] centre. Two conserved cysteines coordinate one Fe ion, while the other Fe ion is coordinated by two conserved histidines. In hyperthermophilic archaea there is a SKTPCX(2-3)C motif at the C-terminus. The cysteines in this motif form a disulphide bridge, which stabilises the protein [4]. [1]. 8736555. Structure of a water soluble fragment of the 'Rieske' iron- sulfur protein of the bovine heart mitochondrial cytochrome bc1 complex determined by MAD phasing at 1.5 A resolution. Iwata S, Saynovits M, Link TA, Michel H. Structure 1996;4:567-579. [2]. 1961737. Functional analysis in yeast of cDNA coding for the mitochondrial Rieske iron-sulfur protein of higher plants. Huang JT, Struck F, Matzinger DF, Levings CS;. Proc Natl Acad Sci U S A 1991;88:10716-10720. [3]. 8386158. The mitochondrial targeting presequence of the Rieske iron-sulfur protein is processed in a single step after insertion into the cytochrome bc1 complex in mammals and retained as a subunit in the complex. Brandt U, Yu L, Yu CA, Trumpower BL;. J Biol Chem 1993;268:8387-8390. [4]. 19862563. Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins. Botelho HM, Leal SS, Veith A, Prosinecki V, Bauer C, Frohlich R, Kletzin A, Gomes CM;. J Biol Inorg Chem. 2010;15:271-281. (from Pfam)

Date:

2024-10-16

This model represents the Proteobacterial and mitochondrial type of the Rieske [2Fe-2S] iron-sulfur as found in ubiquinol-cytochrome c reductase. The model excludes the Rieske iron-sulfur protein as found in the cytochrome b6-f complex of the Cyanobacteria and chloroplasts. Most members of this family have a recognizable twin-arginine translocation (tat) signal sequence (DeltaPh-dependent translocation in chloroplast) for transport across the membrane with the 2Fe-2S group already bound. These signal sequences include a motif resembling RRxFLK before the transmembrane helix.

Gene:

petA

Date:

2021-04-27

ubiquinol-cytochrome c reductase iron-sulfur subunit is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is a respiratory chain that generates an electrochemical potential coupled to ATP synthesis

Date:

2018-03-09