ibclogo XVI International Botanical Congess


Abstract Number: 3329
Poster No. = 1984


IDENTIFICATION OF POTENTIAL REDOX-SENSITIVE CYSTEINE RESIDUES IN THE REDUCTASE DOMAINS OF TWO PLANT DIHYDROFOLATE REDUCTASE-THYMIDYLATE SYNTHASES


Louise E. Anderson, Alex Dong Li, Laura M. Bucher, Chirag Dholakia,Biological Sciences, University of Illinois-Chicago, Chicago IL USAFred J. Stevens, Mechanistic Biology and Biotechnology, Argonne NationalLaboratory, Argonne IL USA


The plant dihydrofolate reductase-thymidylate synthases are bifunctional enzymes that contain several cysteine residues. When we computationally substituted the cysteines in the carrot and Arabidopsis enzymes into the 3-dimensional structure of the Leishmania major enzyme we found potential disulfides in the reductase domains of both enzymes. Treatment of crude extracts with dithiothreitol orglutathione causes marked inhibition of reductase activity. These results suggest that the activity of this enzyme might be subject to redox-regulation in green plants. Supported by US NSF and DOE.


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