title: Identification and functional analysis of bifunctional ent-kaurene synthase from the moss Physcomitrella patens.
abstract: ent-Kaurene is the key intermediate in biosynthesis of gibberellins (GAs), plant hormones. In higher plants, ent-kaurene is synthesized successively by copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS) from geranylgeranyl diphosphate (GGDP). On the other hand, fungal ent-kaurene synthases are bifunctional cyclases with both CPS and KS activity in a single polypeptide. The moss Physcomitrella patens is a model organism for the study of genetics and development in an early land plant. We identified ent-kaurene synthase (PpCPS/KS) from P. patens and analyzed its function. PpCPS/KS cDNA encodes a 101-kDa polypeptide, and shows high similarity with CPSs and abietadiene synthase from higher plants. PpCPS/KS is a bifunctional cyclase and, like fungal CPS/KS, directly synthesizes the ent-kaurene skeleton from GGDP. PpCPS/KS has two aspartate-rich DVDD and DDYFD motifs observed in CPS and KS, respectively. The mutational analysis of two conserved motifs in PpCPS/KS indicated that the DVDD motif is responsible for CPS activity (GGDP to CDP) and the DDYFD motif for KS activity (CDP to ent-kaurene and ent-16alpha-hydroxykaurene).
authors.affiliation: Department of Biochemistry, Okayama University of Science, 1-1 Ridai-cho, Okayama City 700-0005, Japan.
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaide
authors.forename: Miho
authors.initials: M
authors.lastname: Notomi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sakigi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Matsuo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nozaki
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000502:physiology*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D044002:Bryophyta / Q000201:enzymology*; D016297:Mutagenesis, Site-Directed; D010802:Phylogeny; D010940:Plant Proteins; D016415:Sequence Alignment
chemical_list: D010940:Plant Proteins; D019883:Alkyl and Aryl Transferases; C090963:ent-kaurene synthetase A; C105712:ent-kaurene synthetase B