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Asp‐193 and Glu‐218 of subunit II are involved in the Mn 2+ ‐binding of Paracoccus denitrificans cytochrome c oxidase
Author(s) -
Witt Heike,
Wittershagen Axel,
Bill Eckhard,
Kolbesen B.O,
Ludwig Bernd
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00485-7
Subject(s) - paracoccus denitrificans , cytochrome c oxidase , protein subunit , chemistry , electron transport complex iv , biochemistry , stereochemistry , enzyme , gene
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.