PARENT SESSION
Posters P5B Light, redox and metabolic regulation: Dark Reactions. Abstracts (528-530)

Survey and phylogeny of thioredoxin and glutaredoxin families. Renu Srivastava^*,1, Stephen Rudd², Eevi Rintamäki^*,1, ¹ Department of Biology, Turku, Finland² Centre for Biotechnology, Turku, Finland

ABSTRACT- Thioredoxins and glutaredoxins are ubiquitous redox proteins belonging to the thioredoxin superfamily. They regulate several cellular functions via mediating a dithiol/disulphide exchange in target proteins. Thioredoxins are small proteins (12-14 kDa) sharing a conserved redox-active site of W-C-G(P)-P-C. Thioredoxins have been classified into several subgroups based on their structural homologs and their localisation in different compartments of the cell. They are encoded by one to several genes in prokaryotic and eukaryotic organisms. Glutaredoxins are another group of small redox proteins with a motif called thioredoxin fold. On account of the importance of these proteins as regulatory molecules, we carried out EST database survey of Lycopersicon esculentum, Glycine max, Helianthus annus, Secale cereale, Oryza sativa, Solanum tuberosum, Apis mellifera ligustica, Oncorhynchus mykiss, Salmo salar, and whole genome survey for Drosophila melanogaster, Rattus norvegicus and Caenorhabditis briggsae in an attempt to target and extract thioredoxin proteins which have not been characterised to date. Several glutaredoxin and glutaredoxin-like proteins from Ricinus communis, Vercinia fordii, Lycopersicon esculentum, Tilia platyphyllos, Populus tremuloides, Triticum aestivum and Oryza sativa were also characterised. The proteins were aligned and phylogenetic trees were constructed with the aim of establishing interrelationships between the different thioredoxins and glutaredoxins. This analysis helped in determining the consensus sequences amongst the new and already established thioredoxin and glutaredoxin proteins. The proteins could also be assigned and then designated to their respective classes. Subcellular localisation predictions were carried out for these proteins with several computer-based programmes. Our studies have given important preliminary clues on the homologies and localisation of several thioredoxins, glutaredoxins and related proteins. Further analysis of the exact biochemical roles of these proteins, their potential targets in different compartments of the cell needs to be established by various biochemical and molecular approaches.

KEY WORDS: homologs, consensus sequences, thiol regulation