Compelling EPR evidence that the alternative oxidase is a diiron carboxylate protein.
The alternative oxidase is a respiratory chain protein found in plants, fungi and some parasites that still remains physically uncharacterised. In this report we present EPR evidence from parallel mode experiments which reveal signals at approximately g=16 in both purified alternative oxidase protein (g=16.9), isolated mitochondrial membranes (g=16.1), and in trypanosomal AOX expressed in Escherichia coli membranes (g=16.4). Such signals are indicative of a dicarboxylate diiron centre at the active site of the enzyme. To our knowledge these data represent the first EPR signals from AOX present in its native environment.
Moore
Anthony L
AL
Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer Brighton BN1 9QG UK. a.l.moore@sussex.ac.uk
Carré
Jane E
JE
Affourtit
Charles
C
Albury
Mary S
MS
Crichton
Paul G
PG
Kita
Kiyoshi
K
Heathcote
Peter
P
D000818:Animals; D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D007501:Iron / Q000737:chemistry*; D051336:Mitochondrial Membranes / Q000737:chemistry / Q000201:enzymology; D024101:Mitochondrial Proteins; D010088:Oxidoreductases / Q000737:chemistry*; D010940:Plant Proteins; D014345:Trypanosoma / Q000201:enzymology; D000099188:Alternative Oxidase
D007501:Iron; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase