Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The coxII/coxIII operon of Rhodobacter sphaeroides cytochrome c oxidase has been sequenced and characterized by insertional inactivation/complementation analysis. The organization of the genes in this locus (coxII.orf1.orf3.coxIII) is the same as that of the equivalent operon of Paracoccus denitrificans (ctaC.ctaB.ctaG.ctaE), but unlike that of other bacteria whose cytochrome oxidase genes have been characterized so far. The predicted amino acid sequence homology with eukaryotic oxidases is also higher for Rb. sphaeroides (and P. denitrificans) than for other bacterial versions of the enzyme. The inactivation of coxII results in loss of the characteristic cytochrome oxidase spectrum from membranes of the mutant strain. Full recovery requires introduction into the bacterium of the complete operon containing coxII.orf1.orf3.coxIII; partial complementation yielding a spectrally altered enzyme is achieved with a plasmid containing coxII or coxII.orf1.orf3. These results indicate that the peptides ORF1, ORF3, and COXIII are all required for assembly of native cytochrome c oxidase, suggesting an oxidase-specific assembly or chaperonin function for the ORFs in Rb. sphaeroides similar to that observed for the homologous gene products in yeast, COX10 and COX11.
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PMID:Cytochrome aa3 of Rhodobacter sphaeroides as a model for mitochondrial cytochrome c oxidase. The coxII/coxIII operon codes for structural and assembly proteins homologous to those in yeast. 133 50

We have investigated the activity and abundance of a number of respiratory chain components in ripening and cold-treated tomato fruits (Lycopersicon esculentum L. Mill cvv. Moneymaker and Sweetie). Expression of the alternative oxidase (AOX) protein increased dramatically in both situations. Levels of the plant uncoupling protein (UCP) initially fell, but increased substantially in the later stages of ripening. In contrast, ATP synthase subunits and the COXII subunit of cytochrome oxidase decreased during ripening and increased slightly in response to cold stress. Other proteins involved in electron transport, tricarboxylic acid cycle function, chaperonin function, and membrane transport were also studied. These showed varying degrees of enhanced and depressed expression patterns. There were modest changes in whole fruit respiratory activities, and electron transport capacity of isolated mitochondria in response to these stimuli. However, respiratory control by ADP in the isolated mitochondria decreased as AOX capacity and abundance increased, indicating that although total respiration rates changed little, flux between the coupled and uncoupled pathways altered. The changes observed in AOX and UCP accumulation in tomato fruit that were vine-ripened were significantly different from post-harvest ripening patterns previously reported. The altered protein profiles are discussed in the context of on- and off-vine ripening and the potentially different roles of uncoupled respiration in each situation.
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PMID:Mitochondrial protein expression in tomato fruit during on-vine ripening and cold storage. 3268 30