The Iwata bc1 complex structures

The Iwata et al. structures of the bc₁ complex

Click here to load the structure of the P65 complex.
Click here to load the structure of the P6522 complex.
The structures are shown as a backbone models, color-coded by chain, with hetero groups as spacefilling models, and the 2Fe2S center colored CPK.

Restore wireframe view.
Show the metal centers as spacefilling models.
Show the core subunits as spacefilling models.
Show the cytochrome b subunits as spacefilling models.
Show the cytochrome c₁ subunits as spacefilling models.
Show the ISP subunits as spacefilling models.
A more detailed look at the Q_o-site.
- Show Subunit VI as spacefilling models.
- Show Subunit VII as spacefilling models.
- Show Subunit VIII (the hinge protein) as spacefilling models.
- Show Subunit IX as spacefilling models.
- Show Subunit X as spacefilling models.
- Show Subunit XI as spacefilling models.
Show the complete complex as a spacefilling model.

The docking of the ISP with cytochrome c₁

In the P6522 structure, the ISP approaches close to cyt c₁ in a configuration better resolved than in previous structures. This is likely the position from which electron transfer occurs.

Show the interaction between ISP (yellow, with His-161 as a red stick model) and cyt c₁ (blue, with heme in cyan). Atoms within a 6 Å interface are shown; Ca atoms are labeled. The Ne of His-161 is within H-bonding distance of one of the propionate -C=O atoms of cyt c₁. (This may take some time to display)

The "intermediate" position of the ISP

In the P65 structure, one monomer has ISP in a different position, and with a changed conformation, from those previously observed in other structures. The following buttons compare the ISP positions in the equivalent monomers from P65 and P6522 structures.

Load file with ISP from both structures.
Show only P6522 ISP
- Show potential H-bonds (within 3.5 Å) with Glu-109
- Show potential H-bonds (within 3.5 Å) with Arg-170
Show only P65 ISP
- Show potential H-bonds (within 3.5 Å) with Glu-109
- Show potential H-bonds (within 3.5 Å) with Arg-170

Local environment of conserved residues in cytochrome b

Click on the button for a residue and see all potential H-bonding partners within 3.5 Å of that residue. Atoms able to act as H-bond donor or acceptor are shown as ball & stick models, and labeled by residue, number, atom type, and chain. All atoms within 6 Å are shown as stick models, and Ca atoms are labeled by residue, number and chain.
(Numbering is for bovine mitchonrial complex)

Ile19	Asp20	Leu21	Pro22	Trp31
Asn32	Gly34	Leu37	Cys40	Gln44
Gly48	Gly76	His83	Asn85	Gly86	Ser88	Phe90	His97
Arg100	Gly101	Leu102	Tyr103	Tyr104	Ser106	Tyr107	Trp113
Gly116	Gly130	Tyr131	Gln137	Met138	Ser139	Trp141	Val145
Ile146	Thr147	Pro154	Gly157	Gly167	Thr174	Leu175	His182
Phe183	Pro186	His196	Leu200	His201	Gly204	Phe220	Lys227
Asp228	Gly251	Asn255	Asn260	Pro261	Pro270	Glu271	Trp272
Tyr273	Phe274	Leu275	Phe276	Tyr278	Ile280	Leu281	Arg282
Pro285	Lys287	Gly290	Val291	Leu294	Leu335	Trp337	Pro346

To view other residues, and their physico-chemical context, try out the bc₁ complex Chime page with Command Line interface. (Loads "functional" 3-subunit monomer from native chicken bc₁ complex; allows access to all Brookhaven PDB files)

The Iwata et al. structures of the bc1 complex

The docking of the ISP with cytochrome c1

The "intermediate" position of the ISP

Local environment of conserved residues in cytochrome b

The Iwata et al. structures of the bc₁ complex

The docking of the ISP with cytochrome c₁