Plant Biochemistry and Physiology

Plant genomes contain larger families of "-redoxin"-genes than animals and fungi. "Redoxins" are components of the dthiol-/disulifide regulatorx network and include thioredoxins, glutaredoxins and peroxiredoxins. Peroxiredoxins function as thiol-based peroxidases and detoxify hydrogen peroxide, alkyl hydroperoxides and peroxinitrite. The minimum peroxiredoxin inventory of higher plants appears to consist of a nuclear 1-cysteine peroxiredoxin, a plastid 2-cysteine peroxiredoxin, a plastid peroxiredoxin Q, a plastid type II peroxiredoxin E, a mitochondrial PrxIIF and a cytosolic PrxIIC-like peroxiredoxin. Depending on species, single Prx may by present as isoforms, e.g. 2CysPrx A and 2-CysPrxB in Arabidopsis thaliana. The basic mechanism involves a peroxidatic thiol that donates electrons for peroxide reduction. 2-CysPrx undergoes major conformational changes in dependence on the thiol redox state which can be thiol, sulfenic, sulfinic, sulfonic form. The concomitant functional switches from peroxidase, proximity based thiol oxidase, protein interactor and chaperone. These multiple forms and functions assign a central role as a hub of redox signal integration to peroxiredoxins (Muthuramalingam et al. 2008; Dietz 2011).

In this project we mostly use the following methods:

• recombinant protein generation
• site directed mutagenesis
• genetic knock out and complemented Arabidopsis thaliana
• analysis of linked signalling cascades
• protein interaction studies
• transcript regulation