The terminal caa3 oxidase of Thermus thermophilus has been studied by resonance Raman spectroscopy. Using different excitation wavelengths in the Soret band region, it was possible to disentangle the resonance Raman spectra of the fully oxidized and fully reduced state in terms of the component spectra of the individual hemes a, a3, and c. For the heme a and a3 groups, the spectra reveal only minor differences compared to those of beef heart cytochrome c oxidase attributable to subtle modifications of the heme environment. These differences are not more pronounced than those between the oxidases from beef heart and Paracoccus denitrificans confirming the view that this oxidase of Th. thermophilus is a typical member of the aa3 oxidase superfamily. The heme c component spectra display far-reaching similarities with those of c-type cytochromes which serve as mobile electron carriers in the respiratory chain. These results imply that caa3 oxidase represents an integrated version of the noncovalent redox complex between cytochrome c and cytochrome c oxidase in higher organisms. On the other hand, the structural changes of cytochrome c in the noncovalent complex have no counterpart in the heme c component of the caa3 oxidase indicating a specific cytochrome c binding site for the mitochondrial enzyme.
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http://dx.doi.org/10.1002/(SICI)1520-6343(1998)4:6%3C365::AID-BSPY2%3E3.0.CO;2-C | DOI Listing |
Sci Rep
January 2025
Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zürich, 8008, Switzerland.
Burkholderia cenocepacia H111 is an obligate aerobic bacterium which has been isolated from a cystic fibrosis (CF) patient. In CF lungs the environment is considered micro-oxic or even oxygen-depleted due to bacterial activities and limited oxygen diffusion in the mucus layer. To adapt to low oxygen concentrations, bacteria possess multiple terminal oxidases.
View Article and Find Full Text PDFJ Bioenerg Biomembr
December 2024
Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Interior S/N, Ciudad Universitaria, Coyoacán, Ciudad de México, 04510, México.
Bacillus licheniformis can use cyanide as a nitrogen source for its growth. However, it can also carry out aerobic respiration in the presence of this compound, a classic inhibitor of mammalian cytochrome c oxidase, indicating that B. licheniformis has a branched respiratory chain with various terminal oxidases.
View Article and Find Full Text PDFJ Gen Appl Microbiol
November 2023
Center for Interdisciplinary AI and Data Science, Ochanomizu University.
In thermophilic microorganisms, c-type cytochrome (cyt) proteins mainly function in the respiratory chain as electron carriers. Genome analyses at the beginning of this century revealed a variety of genes harboring the heme c motif. Here, we describe the results of surveying genes with the heme c motif, CxxCH, in a genome database comprising four strains of Thermus thermophilus, including strain HB8, and the confirmation of 19 c-type cytochromes among 27 selected genes.
View Article and Find Full Text PDFBiochim Biophys Acta Bioenerg
August 2023
University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal. Electronic address:
Rhodothermus marinus is a thermohalophilic organism that has optimized its microaerobic metabolism at 65 °C. We have been exploring its respiratory chain and observed the existence of a quinone:cytochrome c oxidoreductase complex, named Alternative Complex III, structurally different from the bc complex. In the present work, we took profit from nanodiscs and liposomes technology to investigate ACIII activity in membrane-mimicking systems.
View Article and Find Full Text PDFJ Bioenerg Biomembr
December 2022
Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios #1. Los Reyes Iztacala, 54090, Tlalnepantla, Edo. de México, Mexico.
Bacillus subtilis is a Gram-positive bacterium with a respiratory chain embedded in the cytoplasmic membrane. The respiratory chain is bifurcated after menaquinol into a cytochrome bc + caa branch and a branch with up to three quinol oxidases. The complexes that generate the proton gradient are bc, associated with caa and aa oxidase.
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