Asp‐193 and Glu‐218 of subunit II are involved in the Mn2+‐binding of Paracoccus denitrificans cytochrome c oxidase

• Published in: FEBS letters Vol. 409; no. 2; pp. 128 - 130
• Main Authors: Witt, Heike, Wittershagen, Axel, Bill, Eckhard, Kolbesen, B.O, Ludwig, Bernd
• Format: Journal Article
• Language: English
• Published: England 09-06-1997
• Subjects: Amino Acid Sequence; Aspartic Acid - genetics; Aspartic Acid - metabolism; Aspartic Acid - physiology; electron paramagnetic resonance; Electron Spin Resonance Spectroscopy; Electron transfer; Electron Transport Complex IV - genetics; Electron Transport Complex IV - metabolism; EPR; Glutamic Acid - genetics; Glutamic Acid - metabolism; Glutamic Acid - physiology; Magnesium-binding site; Manganese - metabolism; Mutagenesis, Site-Directed; Non-redox-active metal; Paracoccus denitrificans - enzymology; Paracoccus denitrificans - genetics; Protein Binding - genetics; Terminal oxidase; total-reflection X-ray fluorescence spectrometry; TXRF
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(97)00485-7

Cytochrome c oxidase contains a binding site for a non‐redox‐active metal at the interface of subunits I and II, usually a magnesium ion. In Paracoccus denitrificans oxidase, typically 20% may be replaced by manganese, using standard growth media. Site‐directed mutants were constructed in subunit II (D193N and E218Q), and the isolated enzymes analyzed by total‐reflection X‐ray fluorescence spectrometry and EPR. Both mutants show a strong reduction of the manganese stoichiometry and a diminished electron transfer activity, demonstrating that D193 and E218 are involved in the binding of a manganese/magnesium ion in this site.