1KYO
YEAST CYTOCHROME BC1 COMPLEX WITH BOUND SUBSTRATE CYTOCHROME C
Summary for 1KYO
| Entry DOI | 10.2210/pdb1kyo/pdb |
| Related | 1EZV 1KB9 |
| Descriptor | UBIQUINOL-CYTOCHROME C REDUCTASE COMPLEX CORE PROTEIN I, HEAVY CHAIN (VH) OF FV-FRAGMENT, LIGHT CHAIN (VL) OF FV-FRAGMENT, ... (15 entities in total) |
| Functional Keywords | multisubunit membrane protein complex, enzyme substrate complex, electron transfer complex, antibody fv fragment mediated crystallization, oxidoreductase-electron transport complex, oxidoreductase/electron transport |
| Biological source | Mus musculus (house mouse) More |
| Cellular location | Mitochondrion inner membrane: P07256 P07257 P00127 P00128 P08525 P22289 Mitochondrion intermembrane space: P00044 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 | 23 |
| Total formula weight | 507214.83 |
| Authors | |
| Primary citation | Lange, C.,Hunte, C. Crystal structure of the yeast cytochrome bc1 complex with its bound substrate cytochrome c. Proc.Natl.Acad.Sci.USA, 99:2800-2805, 2002 Cited by PubMed Abstract: Small diffusible redox proteins facilitate electron transfer in respiration and photosynthesis by alternately binding to integral membrane proteins. Specific and transient complexes need to be formed between the redox partners to ensure fast turnover. In respiration, the mobile electron carrier cytochrome c shuttles electrons from the cytochrome bc1 complex to cytochrome c oxidase. Despite extensive studies of this fundamental step of energy metabolism, the structures of the respective electron transfer complexes were not known. Here we present the crystal structure of the complex between cytochrome c and the cytochrome bc1 complex from Saccharomyces cerevisiae. The complex was crystallized with the help of an antibody fragment, and its structure was determined at 2.97-A resolution. Cytochrome c is bound to subunit cytochrome c1 of the enzyme. The tight and specific interactions critical for electron transfer are mediated mainly by nonpolar forces. The close spatial arrangement of the c-type hemes unexpectedly suggests a direct and rapid heme-to-heme electron transfer at a calculated rate of up to 8.3 x 10(6) s(-1). Remarkably, cytochrome c binds to only one recognition site of the homodimeric multisubunit complex. Interestingly, the occupancy of quinone in the Qi site is higher in the monomer with bound cytochrome c, suggesting a coordinated binding and reduction of both electron-accepting substrates. Obviously, cytochrome c reduction by the cytochrome bc1 complex can be regulated in response to respiratory conditions. PubMed: 11880631DOI: 10.1073/pnas.052704699 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.97 Å) |
Structure validation
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