A switch in heme axial ligation prepares Paracoccus pantotrophus cytochrome cd1 for catalysis

Autor:	J W, Allen, N J, Watmough, S J, Ferguson
Rok vydání:	2000
Předmět:	Models Molecular Nitrite Reductases Protein Conformation Cytochromes Cytochrome c Group Heme Paracoccus Oxidation-Reduction Catalysis
Zdroj:	Nature structural biology. 7(10)
ISSN:	1072-8368
Popis:	Cytochrome cd1 nitrite reductase (cd1) from Paracoccus pantotrophus is a respiratory enzyme capable of using nitrite, hydroxylamine and oxygen as electron accepting substrates. Structural studies have shown that when the enzyme is reduced there is a change in the axial ligation of both hemes, which has been proposed to form part of the catalytic cycle. Here we report the use of a physiological electron donor, pseudoazurin, to investigate the relationship between heme ligation and catalysis. A combination of visible absorption and electron paramagnetic resonance spectroscopies reveals the formation of a catalytically competent state of oxidized cd1 with 'switched' axial ligands immediately after complete reoxidation of reduced cd1 with hydroxylamine. This activated conformer returns over 20 min at 25 degrees C to the state previously observed for oxidized 'as isolated' cd1, which is catalytically inactive towards the same substrates.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=pmid________::62a0a6c3fadbcd604f227bc2a693395f https://pubmed.ncbi.nlm.nih.gov/11017198 Zobrazit plný text záznamu Full text from SpringerLink