1KB9

YEAST CYTOCHROME BC1 COMPLEX

Summary for 1KB9

• Entry DOI: 10.2210/pdb1kb9/pdb
• Related: 1EZV
• Descriptor: UBIQUINOL-CYTOCHROME C REDUCTASE COMPLEX CORE PROTEIN I, HEAVY CHAIN (VH) OF FV-FRAGMENT, LIGHT CHAIN (VL) OF FV-FRAGMENT, ... (21 entities in total)
• Functional Keywords: oxidoreductase, ubiquinone, stigmatellin, cardiolipin, phosphatidylinositol, phosphatidylcholin, phosphatidylethanolamin, undecyl-maltopyranoside, oxidoreductase-electron transport complex, oxidoreductase/electron transport
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Cellular location: Mitochondrion inner membrane: P07256 P07257 P00127 P00128 P08525 P22289; Mitochondrion inner membrane; Multi-pass membrane protein: P00163; Mitochondrion inner membrane; Single-pass membrane protein; Intermembrane side: P07143; Mitochondrion: P08067
• Total number of polymer chains: 11
• Total formula weight: 252223.09

Authors

Lange, C.,Nett, J.H.,Trumpower, B.L.,Hunte, C. (deposition date: 2001-11-05, release date: 2002-09-18, Last modification date: 2024-10-16)

Primary citation

Lange, C.,Nett, J.H.,Trumpower, B.L.,Hunte, C.
SPECIFIC ROLES OF PROTEIN-PHOSPHOLIPID INTERACTIONS IN THE YEAST CYTOCHROME BC1 COMPLEX STRUCTURE
EMBO J., 20:6591-6600, 2001

PubMed Abstract: Biochemical data have shown that specific, tightly bound phospholipids are essential for activity of the cytochrome bc1 complex (QCR), an integral membrane protein of the respiratory chain. However, the structure and function of such phospholipids are not yet known. Here we describe five phospholipid molecules and one detergent molecule in the X-ray structure of yeast QCR at 2.3 A resolution. Their individual binding sites suggest specific roles in facilitating structural and functional integrity of the enzyme. Interestingly, a phosphatidylinositol molecule is bound in an unusual interhelical position near the flexible linker region of the Rieske iron-sulfur protein. Two possible proton uptake pathways at the ubiquinone reduction site have been identified: the E/R and the CL/K pathway. Remarkably, cardiolipin is positioned at the entrance to the latter. We propose that cardiolipin ensures structural integrity of the proton-conducting protein environment and takes part directly in proton uptake. Site-directed mutagenesis of ligating residues confirmed the importance of the phosphatidylinositol- and cardiolipin-binding sites.

PubMed: 11726495
DOI: 10.1093/emboj/20.23.6591

Experimental method

X-RAY DIFFRACTION (2.3 Å)