Study guide focuses on how the three polypeptides which are involved in the redox reactions are structurally related to each other and the other peptides which are in the 22 polypeptide dimer and on how these structural relationships permit the passing of the electrons resulting in the moving of protons to the intermembrane space.

Chapter 1

An overview of the structure of the 22 polypeptide mitochondrial complex III is given including its orientation in the mitochondrial inner membrane. The positions within this complex of the three proteins involved in the mitochondrial redox reactions are presented, and the positions of these three proteins with respect to each other are described.

Chapter 2

The focus is on the three proteins - cytochrome b, cytochrome c1 and Rieske protein - involved in the redox reactions. The ligands which are involved in the redox reactions are described as to their chemical natures and their positions within the proteins.

Chapter 3

The first half of the Q cycle is described and illustrated. If you are unfamiliar with the Q cycle, it is recommended that you read about the cycle in a biochemistry text.

Chapter 4

The second half of the Q cycle is described and illustrated.

Chapter 5

Review of the structure of the complete Complex III. Description of how the subunits of the dimer work in concert to accomplish what they could not achieve by working as a single unit.

 

1. S. Iwata, et al., Science, 281, 64, (1998)
2. Z. Zhang, et al., Nature, 392, 677, (1998)
3. D. Xia, et al., Science, 277, 60 (1997)

This is a Presentation in Protein Explorer (PiPE) prepared with proteinexplorer.org. Development of Protein Explorer was supported by a grant to Eric Martz from the Division of Undergraduate Education of the US National Science Foundation.