RECENT DEVELOPMENTS IN THE STUDY OF THE STRUCTURE-FUNCTION RELATIONSHIP OF FLAVONOL SULFOTRANSFERASES

With the rapid proliferation of sulfotransferase (ST) cDNA sequences i n the last 5 years, consensus sequences were identified in four conser ved regions. The association of these regions with substrate binding o r catalysis was tested in several site-directed mutagenesis studies. D ue to their strict substrate and position specificities, the flavonol 3- and 4'-STs represent an advantageous model system for the study of the structure-function relationship of cytosolic STs. Using a combinat ion of chimeric and site-directed mutant proteins, a domain was identi fied containing all the determinants responsible for the substrate spe cificity of these enzymes, and characterized amino acid residues conse rved in all cloned STs that are involved in substrate binding and cata lysis. This paper summarizes the results of these studies. (C) 1998 El sevier Science Ireland Ltd. All rights reserved.