6CI0

Catalytic core subunits (I and II) of cytochrome C oxidase from Rhodobacter sphaeroides with E101A (II) mutation

Summary for 6CI0

• Entry DOI: 10.2210/pdb6ci0/pdb
• Related: 2GSM
• Related PRD ID: PRD_900001
• Descriptor: Cytochrome c oxidase subunit 1, CADMIUM ION, (2S,3R)-heptane-1,2,3-triol, ... (14 entities in total)
• Functional Keywords: oxidase, electron transfer, proton pumping, oxidoreductase
• Biological source: Rhodobacter sphaeroides (Rhodopseudomonas sphaeroides); More
• Total number of polymer chains: 4
• Total formula weight: 187629.43

Authors

Liu, J.,Hiser, C.,Ferguson-Miller, S. (deposition date: 2018-02-23, release date: 2018-04-25, Last modification date: 2024-10-09)

Primary citation

Hiser, C.,Liu, J.,Ferguson-Miller, S.
The K-path entrance in cytochrome c oxidase is defined by mutation of E101 and controlled by an adjacent ligand binding domain.
Biochim. Biophys. Acta, 1859:725-733, 2018

PubMed Abstract: Three mutant forms of Rhodobacter sphaeroides cytochrome c oxidase (RsCcO) were created to test for multiple K-path entry sites (E101W), the existence of an "upper ligand site" (M350 W), and the nature and binding specificity of the "lower ligand site" (P315W/E101A) in the region of a crystallographically-defined deoxycholate at the K-path entrance. The effects of inhibitory and stimulatory detergents (dodecyl maltoside and Tween20) on these mutants are presented, as well as competition with other ligands, including the potentially physiologically relevant ligands cholesterol and retinoic acid. Ligands are shown to be able to compete with natural lipids to affect the activity of membrane-bound RsCcO. Results point to a single K-path entrance site at E101, with a single ligand binding pocket proximal to the entrance. The affinity of this pocket for amphipathic ligands is enhanced by removal of the E101 carboxyl and blocked by substituting a tryptophan in this area. A new crystal structure of the E101A mutant of RsCcO is presented that illustrates the structural basis of these results, showing that the loss of the E101 carboxyl creates a more hydrophobic groove consistent with altered ligand affinities.

PubMed: 29626419
DOI: 10.1016/j.bbabio.2018.03.017

Experimental method

X-RAY DIFFRACTION (2.4 Å)