COR1/YBL045C Summary Help

Standard Name COR1 1
Systematic Name YBL045C
Alias QCR1
Feature Type ORF, Verified
Description Core subunit of the ubiquinol-cytochrome c reductase complex; the ubiquinol-cytochrome c reductase complex (bc1 complex) is a component of the mitochondrial inner membrane electron transport chain (1 and see Summary Paragraph)
Name Description CORe protein of QH2 cytochrome c reductase 1
Chromosomal Location
ChrII:135516 to 134143 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All COR1 GO evidence and references
  View Computational GO annotations for COR1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 4 genes
Classical genetics
Large-scale survey
193 total interaction(s) for 132 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 105
  • Affinity Capture-RNA: 4
  • Affinity Capture-Western: 51
  • Co-crystal Structure: 1
  • Reconstituted Complex: 1
  • Two-hybrid: 3

Genetic Interactions
  • Negative Genetic: 12
  • Positive Genetic: 13
  • Synthetic Growth Defect: 2
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 457
Molecular Weight (Da) 50,227
Isoelectric Point (pI) 7.34
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:135516 to 134143 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1374 135516..134143 2011-02-03 1997-01-28
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000141

The cytochrome bc1 complex (also known as ubiquinol:cytochrome c oxidoreductase, ubiquinol:ferricytochrome c oxidoreductase, and respiratory complex III) is a highly conserved enzyme of the mitochondrial respiratory chain (reviewed in 2). In S. cerevisiae it consists of three catalytic subunits, Cobp, Rip1p, and Cyt1p, plus seven additional subunits: Cor1p, Qcr2p, Qcr6p, Qcr7p, Qcr8p, Qcr9p, and Qcr10p (2, 3). The crystal structure of the complex shows that two functional units, each containing these ten subunits, associate with each other in the mitochondrial inner membrane (4). Assembly of a functional complex requires two proteins, Cbp3p and Cbp4p, that are not components of the complex but may associate with it during assembly (5). It also requires Bcs1p, an AAA-family ATPase that interacts with a precursor of the complex to mediate incorporation of the Rip1p and Qcr10p subunits (6). The mechanism of energy transfer by the complex, known as the protonmotive Q cycle, has been studied in detail (reviewed in 2). The net result of the Q cycle is the stepwise transfer of an electron through the complex from ubiquinol to cytochrome c (Cyc1p), coupled with the translocation of a proton across the mitochondrial inner membrane (2). The function of the cytochrome bc1 complex is essential to the energy-generating process of oxidative phosphorylation, which is carried out by the enzyme complexes of the mitochondrial respiratory chain.

Cor1p, one of the so-called "core" subunits, is essential for assembly and activity of the cytochrome bc1 complex and thus for respiratory growth; in the null mutant the heme group is not inserted into cytochrome b (Cobp; 1, 7). Cor1p, Qcr2p, and Qcr7p comprise a large domain of the cytochrome bc1 complex that extends into the mitochondrial matrix (2).

COR1 is conserved in other eukaryotes, and its human homolog is UQCRC1 (OMIM; 8). Cor1p has sequence similarity to mitochondrial processing peptidases that remove N-terminal targeting sequences from proteins during import into mitochondria (9). The Neurospora crassa Cor1p homolog has been demonstrated to function both as a cytochrome bc1 complex subunit and as a "processing enhancing protein" that contributes to the proteolytic activity of the mitochondrial processing peptidase, but such a dual function has not been demonstrated for S. cerevisiae Cor1p and the significance of the sequence similarity is unclear (9).

Last updated: 2007-07-26 Contact SGD

References cited on this page View Complete Literature Guide for COR1
1) Tzagoloff A, et al.  (1986) Assembly of the mitochondrial membrane system. Characterization of COR1, the structural gene for the 44-kilodalton core protein of yeast coenzyme QH2-cytochrome c reductase. J Biol Chem 261(36):17163-9
2) Hunte C, et al.  (2003) Protonmotive pathways and mechanisms in the cytochrome bc1 complex. FEBS Lett 545(1):39-46
3) Brandt U, et al.  (1994) Isolation and characterization of QCR10, the nuclear gene encoding the 8.5-kDa subunit 10 of the Saccharomyces cerevisiae cytochrome bc1 complex. J Biol Chem 269(17):12947-53
4) Hunte C, et al.  (2000) Structure at 2.3 A resolution of the cytochrome bc(1) complex from the yeast Saccharomyces cerevisiae co-crystallized with an antibody Fv fragment. Structure 8(6):669-84
5) Kronekova Z and Rodel G  (2005) Organization of assembly factors Cbp3p and Cbp4p and their effect on bc(1) complex assembly in Saccharomyces cerevisiae. Curr Genet 47(4):203-12
6) Cruciat CM, et al.  (1999) Bcs1p, an AAA-family member, is a chaperone for the assembly of the cytochrome bc(1) complex. EMBO J 18(19):5226-33
7) Gatti DL and Tzagoloff A  (1990) Structure and function of the mitochondrial bc1 complex. Properties of the complex in temperature-sensitive cor1 mutants. J Biol Chem 265(35):21468-75
8) Trumpower BL  (1990) Cytochrome bc1 complexes of microorganisms. Microbiol Rev 54(2):101-29
9) Gencic S, et al.  (1991) Core I protein of bovine ubiquinol-cytochrome-c reductase; an additional member of the mitochondrial-protein-processing family. Cloning of bovine core I and core II cDNAs and primary structure of the proteins. Eur J Biochem 199(1):123-31