3OMI

Catalytic core subunits (I and II) of cytochrome C oxidase from Rhodobacter sphaeroides with D132A mutation

Summary for 3OMI

• Entry DOI: 10.2210/pdb3omi/pdb
• Related: 2GSM 3OM3 3OMA 3OMN
• Descriptor: Cytochrome c oxidase, aa3 type, subunit I, CHLORIDE ION, (2S,3R)-heptane-1,2,3-triol, ... (14 entities in total)
• Functional Keywords: transmembrane protein complex, oxidoreductase
• Biological source: Rhodobacter sphaeroides 2.4.1; More
• Cellular location: Cell membrane ; Multi-pass membrane protein : Q3J5A7 Q3J5G0
• Total number of polymer chains: 4
• Total formula weight: 187819.55

Authors

Liu, J.,Qin, L.,Ferguson-Miller, S. (deposition date: 2010-08-27, release date: 2011-02-02, Last modification date: 2017-11-08)

Primary citation

Liu, J.,Qin, L.,Ferguson-Miller, S.
Crystallographic and online spectral evidence for role of conformational change and conserved water in cytochrome oxidase proton pump.
Proc.Natl.Acad.Sci.USA, 108:1284-1289, 2011

PubMed Abstract: Crystal structures in both oxidized and reduced forms are reported for two bacterial cytochrome c oxidase mutants that define the D and K proton paths, showing conformational change in response to reduction and the loss of strategic waters that can account for inhibition of proton transfer. In the oxidized state both mutants of the Rhodobacter sphaeroides enzyme, D132A and K362M, show overall structures similar to wild type, indicating no long-range effects of mutation. In the reduced state, the mutants show an altered conformation similar to that seen in reduced wild type, confirming this reproducible, reversible response to reduction. In the strongly inhibited D132A mutant, positions of residues and waters in the D pathway are unaffected except in the entry region close to the mutation, where a chloride ion replaces the missing carboxyl and a 2-Å shift in N207 results in loss of its associated water. In K362M, the methionine occupies the same position as the original lysine, but K362- and T359-associated waters in the wild-type structure are missing, likely accounting for the severe inhibition. Spectra of oxidized frozen crystals taken during X-ray radiation show metal center reduction, but indicate development of a strained configuration that only relaxes to a native form upon annealing. Resistance of the frozen crystal to structural change clarifies why the oxidized conformation is observable and supports the conclusion that the reduced conformation has functional significance. A mechanism is described that explains the conformational change and the incomplete response of the D-path mutant.

PubMed: 21205904
DOI: 10.1073/pnas.1012846108

Experimental method

X-RAY DIFFRACTION (2.15 Å)