title: Temperature-dependent modulation of farnesyl diphosphate/geranylgeranyl diphosphate synthase from hyperthermophilic archaea.
abstract: Enzyme characteristics of trans-prenyl diphosphate synthase (Tk-IdsA) from Thermococcus kodakaraensis, which catalyzes the consecutive trans-condensation of isopentenyl diphosphate (C(5)) units with allylic diphosphate, were examined. Product analysis revealed that Tk-IdsA is a bifunctional enzyme, farnesyl diphosphate (FPP, C(15))/geranylgeranyl diphosphate (GGPP, C(20)) synthase, and mainly yields both C(15) and C(20). The FPP/GGPP product ratio increases with the rise of the reaction temperature. The kinetic parameters obtained at 70 and 90 degrees C demonstrated that the rise of the temperature elevates the k(0) value for the C(10) allylic substrate to more than those for the C(5) and C(15) allylic substrates. These data suggest that Tk-IdsA contributes to adjust the membrane composition to the cell growth temperature by modulating its substrate and product specificities. Mutation study indicated that the aromatic side chain of Tyr-81 acts as a steric hindrance to terminate the chain elongation and defines the final product length.
authors.affiliation: Department of Bioscience, Nanobiotechnology Research Center, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen Sanda, Hyogo 669-1337, Japan. fujiwara@ksc.kwansei.ac.jp
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Aiko
authors.initials: A
authors.lastname: Yamanaka
authors.forename: Kazutake
authors.initials: K
authors.lastname: Hirooka
authors.forename: Akio
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Imanaka
authors.forename: Ei-Ichiro
authors.initials: E
authors.lastname: Fukusaki
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000145:classification / Q000235:genetics; D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology / Q000235:genetics; D004789:Enzyme Activation; D004795:Enzyme Stability; D019848:Gene Expression Regulation, Archaeal / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D051228:Geranyltranstransferase; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D019712:Thermococcus / Q000201:enzymology* / Q000235:genetics
chemical_list: D007527:Isoenzymes; D011994:Recombinant Proteins; D019883:Alkyl and Aryl Transferases; D051228:Geranyltranstransferase