Thioredoxin Ch1 of Chlamydomonas reinhardtii displays an unusual resistance toward one-electron oxidation.
To test thioredoxin resistance to oxidizing free radicals, we have studied the one-electron oxidation of wild-type thioredoxin and of two forms with the point mutations D30A and W35A, using azide radicals generated by gamma-ray or pulse radiolysis. The oxidation patterns of wild-type thioredoxin and D30A are similar. In these forms, Trp35 is the primary target and is 'repaired' by one-electron reduction; first by intramolecular electron transfer from tyrosine, and then from other residues. Conversely, during oxidation of W35A, Trp13 is poorly reactive. For all proteins, activity is conserved showing an unusual resistance toward oxidation.
Laboratoire de Chimie Physique, Université Paris XI, Orsay, France. cecile.sicard@lcp.u-psud.fr
Cécile
C
Sicard-Roselli
Stéphane
S
Lemaire
Jean-Pierre
JP
Jacquot
Vincent
V
Favaudon
Christophe
C
Marchand
Chantal
C
Houée-Levin
D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000378:metabolism / Q000528:radiation effects; D004583:Electrons; D005609:Free Radicals / Q000378:metabolism; D005720:Gamma Rays; D006801:Humans; D007328:Insulin / Q000378:metabolism; D010084:Oxidation-Reduction; D017354:Point Mutation; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D020418:Algal Proteins; D005609:Free Radicals; D007328:Insulin; D015800:Protozoan Proteins; D013879:Thioredoxins