2YIU

X-ray structure of the dimeric cytochrome BC1 complex from the soil bacterium paracoccus denitrificans at 2.7 angstrom resolution

Summary for 2YIU

• Entry DOI: 10.2210/pdb2yiu/pdb
• Descriptor: CYTOCHROME B, CYTOCHROME C1, HEME PROTEIN, UBIQUINOL-CYTOCHROME C REDUCTASE IRON-SULFUR SUBUNIT, ... (8 entities in total)
• Functional Keywords: oxidoreductase
• Biological source: PARACOCCUS DENITRIFICANS; More
• Cellular location: Cell membrane; Multi-pass membrane protein (Potential): P05418; Cell membrane; Single-pass membrane protein (Potential): P13627; Cell membrane; Single-pass membrane protein: P05417
• Total number of polymer chains: 6
• Total formula weight: 205782.81

Authors

Kleinschroth, T.,Castellani, M.,Trinh, C.H.,Morgner, N.,Brutschy, B.,Ludwig, B.,Hunte, C. (deposition date: 2011-05-16, release date: 2011-10-26, Last modification date: 2024-10-23)

Primary citation

Kleinschroth, T.,Castellani, M.,Trinh, C.H.,Morgner, N.,Brutschy, B.,Ludwig, B.,Hunte, C.
X-Ray Structure of the Dimeric Cytochrome Bc(1) Complex from the Soil Bacterium Paracoccus Denitrificans at 2.7-A Resolution.
Biochim.Biophys.Acta, 1807:1606-, 2011

PubMed Abstract: The respiratory cytochrome bc(1) complex is a fundamental enzyme in biological energy conversion. It couples electron transfer from ubiquinol to cytochrome c with generation of proton motive force which fuels ATP synthesis. The complex from the α-proteobacterium Paracoccus denitrificans, a model for the medically relevant mitochondrial complexes, lacked structural characterization. We show by LILBID mass spectrometry that truncation of the organism-specific, acidic N-terminus of cytochrome c(1) changes the oligomerization state of the enzyme to a dimer. The fully functional complex was crystallized and the X-ray structure determined at 2.7-Å resolution. It has high structural homology to mitochondrial complexes and to the Rhodobacter sphaeroides complex especially for subunits cytochrome b and ISP. Species-specific binding of the inhibitor stigmatellin is noteworthy. Interestingly, cytochrome c(1) shows structural differences to the mitochondrial and even between the two Rhodobacteraceae complexes. The structural diversity in the cytochrome c(1) surface facing the ISP domain indicates low structural constraints on that surface for formation of a productive electron transfer complex. A similar position of the acidic N-terminal domains of cytochrome c(1) and yeast subunit QCR6p is suggested in support of a similar function. A model of the electron transfer complex with membrane-anchored cytochrome c(552), the natural substrate, shows that it can adopt the same orientation as the soluble substrate in the yeast complex. The full structural integrity of the P. denitrificans variant underpins previous mechanistic studies on intermonomer electron transfer and paves the way for using this model system to address open questions of structure/function relationships and inhibitor binding.

PubMed: 21996020
DOI: 10.1016/J.BBABIO.2011.09.017

Experimental method

X-RAY DIFFRACTION (2.7 Å)