Jean-Pierre Jacquot: "Thioredoxin and glutaredoxin play a prominent role in stress defence and iron sulfur assembly in plants"

Jean-Pierre Jacquot
Université de Lorraine, France

Thioredoxin and glutaredoxin play a prominent role in stress defence and iron sulfur assembly in plants

Thioredoxin and glutaredoxin are small molecular weight (typically 100-150 AA) enzymes which possess a similar 3D fold called the thioredoxin motif. Many proteins have evolved structurally based on similar constructions as for example protein disulfide isomerases and thiol peroxidases, otherwise known as peroxiredoxins. The basis of catalysis of thioredoxin requires a catalytic cysteine which attacks the disulfide of a target protein, leaving the target reduced and thioredoxin oxidized. For this reason thioredoxins (and glutaredoxins) have to be constantly regenerated at the expense of either NADPH or reduced ferredoxin in the chloroplasts. Unlike in bacteria and animals, glutaredoxins and thioredoxins belong to large multigenic families in plants and especially in land plants. Using selected examples it will be demonstrated in this seminar that these proteins are involved in the regulation of photosynthesis, but also in stress defence reactions (together with peroxiredoxins and methionine sulfoxide reductases). Finally the specific involvement of monothiol glutaredoxins in irons sulfur assembly will be discussed.