| P18946 | n/a | 4u3f | Y52 | C | 503 | e4u3fC1 | Transmembrane heme-binding four-helical bundle | Transmembrane heme-binding four-helical bundle | Transmembrane di-heme cytochromes | Cytochrome_B |
| P18946 | n/a | 4u3f | Y52 | C | 503 | e4u3fC2 | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | Cytochrom_B_C |
| P18946 | n/a | 4u3f | Y52 | P | 404 | e4u3fP1 | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) | Cytochrom_B_C |
| P18946 | n/a | 4u3f | Y52 | P | 404 | e4u3fP2 | Transmembrane heme-binding four-helical bundle | Transmembrane heme-binding four-helical bundle | Transmembrane di-heme cytochromes | Cytochrome_B |