title: Characterization of homogentisate prenyltransferases involved in plastoquinone-9 and tocochromanol biosynthesis.
abstract: A cDNA of Chlamydomonas reinhardtii encoding a plastidial homogentisate prenyltransferase was identified. Functional expression studies in Escherichia coli revealed that the enzyme possessed properties similar to the prenyltransferase of Arabidopsis thaliana encoded by At3g11950 but different from the phytyltransferases of A. thaliana and Synechocystis. Unlike the phytyltransferases, the C. reinhardtii and the respective A. thaliana enzyme showed highest activities with solanesyl diphosphate, but were hardly active with phytyl diphosphate. Hence, these data provide evidence that the latter represent homogentisate solanesyltransferases involved in plastoquinone-9 biosynthesis. Overexpression of At3g11950 in A. thaliana, however, suggests that the solanesyltransferase can affect tocopherol biosynthesis as well.
authors.affiliation: RWTH Aachen University, Institute for Biology I, Botany, Worringerweg 1, 52056 Aachen, Germany. rsadre@bio1.rwth-aachen.de
authors.forename: Radin
authors.initials: R
authors.lastname: Sadre
authors.forename: Jens
authors.initials: J
authors.lastname: Gruber
authors.forename: Margrit
authors.initials: M
authors.lastname: Frentzen
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics*; D004122:Dimethylallyltranstransferase / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D010971:Plastoquinone / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D046939:Synechocystis / Q000201:enzymology / Q000235:genetics; D024505:Tocopherols / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D029968:Escherichia coli Proteins; D015800:Protozoan Proteins; D004122:Dimethylallyltranstransferase; D010971:Plastoquinone; D024505:Tocopherols