ISOLATION AND CHARACTERIZATION OF CDNAS ENCODING IMIDAZOLEGLYCEROLPHOSPHATE DEHYDRATASE FROM ARABIDOPSIS-THALIANA

cDNA clones encoding imidazoleglycerolphosphate dehydratase (IGPD; EC 4.2.1.19) from Arabidopsis thaliana were isolated by complementation o f a bacterial auxotroph. The predicted primary translation product sha red significant identity with the corresponding sequences from bacteri a and fungi. As in yeast, the plant enzyme is monofunctional, lacking the histidinol phosphatase activity present in the Escherichia coli pr otein. IGPD mRNA was present in major organs at all developmental stag es assayed. The Arabidopsis genome appears to contain two genes encodi ng this enzyme, based on DNA gel blot and polymerase chain reaction an alysis.