Chain length determination of prenyltransferases: both heteromeric subunits of medium-chain (E)-prenyl diphosphate synthase are involved in the product chain length determination

Among prenyltransferases, medium-chain (E)-prenyl diphosphate synthases are unusual because of their heterodimeric structures. The larger subunit has highly conserved regions typical of (E)-prenyltransferases. The smaller one has recently been shown to be involved in the binding of allylic substrate as well as determining the chain length of the reaction product [Zhang, Y.-W., et al. (1999) Biochemistry 38, 14638-14643]. To better understand the product chain length determination mechanism of these enzymes, several amino acid residues in the larger subunits of Micrococcus luteus B-P 26 hexaprenyl diphosphate synthase and Bacillus subtilis heptaprenyl diphosphate synthase were selected for substitutions by site-directed mutagenesis and examined by combination with the corresponding wild-type or mutated smaller subunits. Replacement of the Ala at the fifth position upstream to the first Asp-rich motif with bulky amino acids in both larger subunits resulted in shortening the chain lengths of the major products, and a double combination of mutant subunits of the heptaprenyl diphosphate synthase, I-D97A/II-A79F, yielded exclusively geranylgeranyl diphosphate. However, the combination of a mutant subunit and the wild-type, I-Y103S/II-WT or I-WT/II-I76G, produced a C(40) prenyl diphosphate, and the double combination of the mutants, I-Y103S/II-I76G, gave a reaction product with longer prenyl chain up to C(50). These results suggest that medium-chain (E)-prenyl diphosphate synthases take a novel mode for the product chain length determination, in which both subunits cooperatively participate in maintaining and determining the product specificity of each enzyme.     

Directed evolution of Escherichia coli farnesyl diphosphate synthase (IspA) reveals novel structural determinants of chain length specificity

Directed evolution of farnesyl diphosphate (FPP, C15) synthase (IspA) of Escherichia coli was carried out by error-prone PCR with a color complementation screen utilizing C40 carotenoid pathway enzymes. This allowed IspA mutants with enhanced production of the C40 carotenoid precursor geranylgeranyl diphosphate (GGPP, C20) to be readily identified. Analysis of these mutants was carried out in order to better understand the mechanisms of product chain length specificity in this enzyme. The 12 evolved clones having enhanced C20 GGPP production have characteristic mutations in the conserved regions of prenyl diphosphate synthases (designated regions I through VII). Some of these mutations (I76T, Y79S, Y79H, C75Y, H83Y, and H83Q) are found near or before the conserved first aspartate rich motif (FARM), which is involved in the mechanism for chain elongation reaction of all prenyl synthases. Molecular modeling suggested a mechanism for chain length determination for these mutations including substitutions at the 1st and 9th amino acids upstream of the FARM that have not been reported previously. In addition, a mutation on a helix adjacent to the FARM within the substrate-binding pocket (D115G) suggests a novel mechanism for chain length determination. One mutant IspA clone carries a mutation of C155G at the 2nd amino acid upstream of conserved region IV (GQxxDL), which was recently found to be an important region controlling the chain elongation of a Type III GGPP synthase. One IspA clone carries mutations (T234A and T249I) near the conserved second aspartate rich motif (SARM). As a verification of the in vivo activity of the mutant clones (represented as C40 carotenoid formation), we confirmed the product distribution of wild-type and mutant IspA using an in vitro assay.     

Artificial substrates of medium-chain elongating enzymes, hexaprenyl- and heptaprenyl diphosphate synthases

We examined the reactivity of 3-alkyl group homologues of farnesyl diphosphate or isopentenyl diphosphate for medium-chain prenyl diphosphate synthases, hexaprenyl diphosphate- or heptaprenyl diphosphate synthase. But-3-enyl diphosphate, which lacks the methyl group at the 3-position of isopentenyl diphosphate, condensed only once with farnesyl diphosphate to give E-norgeranylgeranyl diphosphate by the action of either enzyme. However, norfarnesyl diphosphate was never accepted as an allylic substrate at all. 3-Ethylbut-3-enyl diphosphate also reacted with farnesyl diphosphate giving a mixture of (all-E)-3-ethyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl- and (all-E)-3,7-diethyl-11,15,19-trimethylicosa-2,6,10,14,18-pentaenyl diphosphates by hexaprenyl diphosphate synthase. On the other hand, heptaprenyl diphosphate synthase reaction of 3-ethylbut-3-enyl diphosphate with farnesyl diphosphate gave only (all-E)-3-ethyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl diphosphate.     

An alternative mechanism of product chain-length determination in type III geranylgeranyl diphosphate synthase.

(All-E) prenyl diphosphate synthases catalyze the consecutive condensation of isopentenyl diphosphates with allylic prenyl diphosphates, producing products with various chain-lengths that are unique for each enzyme. Some short-chain (all-E) prenyl diphosphate synthases, i.e. farnesyl diphosphate synthases and geranylgeranyl diphosphate synthases contain characteristic amino acid sequences around the allylic substrate binding sites, which have been shown to play a role in determining the chain-length of the product. However, among these enzymes, which are classified into several types based on the possessive patterns of such characteristics, type III geranylgeranyl diphosphate synthases, which consist of enzymes from eukaryotes (excepting plants), lack these features. In this study, we report that mutagenesis at the second position before the conserved G(Q/E) motif, which is distant from the well-studied region, affects the chain-length of the product for a type III geranylgeranyl diphosphate synthase from Saccharomyces cerevisiae. This clearly suggests that a novel mechanism is operative in the product determination for this type of enzyme. We also show herein that mutagenesis at the corresponding position of an archaeal medium-chain enzyme also alters its product specificity. These results provide valuable information on the molecular evolution of (all-E) prenyl diphosphate synthases.     

Product chain-length determination mechanism of Z,E-farnesyl diphosphate synthase

cis-Prenyltransferases catalyze the consecutive condensation of isopentenyl diphosphate (IPP) with allylic prenyl diphosphates, producing Z,E-mixed prenyl diphosphate. The Mycobacterium tuberculosis Z,E-farnesyl diphosphate synthase Rv1086 catalyzes the condensation of one molecule of IPP with geranyl diphosphate to yield Z,E-farnesyl diphosphate and is classified as a short-chain cis-prenyltransferase. To elucidate the chain-length determination mechanism of the short-chain cis-prenyltransferase, we introduced some substitutive mutations at the characteristic amino acid residues of Rv1086. Among the mutants constructed, L84A showed a dramatic change of catalytic function to synthesize longer prenyl chain products than that of wild type, indicating that Leu84 of Rv1086 plays an important role in product chain-length determination. Mutagenesis at the corresponding residue of a medium-chain cis-prenyltransferase, Micrococcus luteus B-P 26 undecaprenyl diphosphate synthase also resulted in the production of different prenyl chain length from the intrinsic product, suggesting that this position also plays an important role in product chain-length determination for medium-chain cis-prenyltransferases.     

Interconversion of the product specificity of type I eubacterial farnesyl diphosphate synthase and geranylgeranyl diphosphate synthase through one amino acid substitution

Prenyltransferases catalyze the sequential condensation of isopentenyl diphosphate into prenyl diphosphates with specific chain lengths. Pioneering studies demonstrated that the product specificities of type I prenyltransferases were mainly determined by the amino acid residues at the 4th and 5th positions before the first aspartate-rich motif (FARM) of the prenyltransferases. We previously cloned a type I geranylgeranyl diphosphate synthase (GGDPSase) gene from Streptomyces griseolosporeus MF730-N6 [Hamano, Y., Dairi, T., Yamamoto, M., Kawasaki, T., Kaneda, K., Kuzuyama, T., Itoh, N., and Seto, H. (2001) BIOSCI: Biotechnol. Biochem. 65, 1627-1635]. In this study, a prenyltransferase gene was cloned from Streptomyces argenteolus A-2 and was confirmed to encode a type I farnesyl diphosphate synthase (FDPSase). Interestingly, the amino acid residues at the 4th and 5th positions before the FARM were the same in these two enzymes. To identify the amino acid that determines the product chain length, mutated enzymes, GGDPSase (L-50S), FDPSase (S-50L), GGDPSase (V-8A), FDPSase (A-8V), GGDPSase (A+57L), and FDPSase (L+58A), in which the amino acid residue at the -50th, -8th, and +57th (58th) position before or after the FARM was substituted with the corresponding amino acid of the other enzyme, were constructed. The GGDPSase (A+57L) and FDPSase (L+58A) produced farnesyl diphosphate and geranylgeranyl diphosphate, respectively. On the other hand, the other mutated enzymes produced prenyl diphosphates with the same chain lengths as the wild type enzymes did. These results showed that the amino acid residue at the 57th (58th) position after the FARM also played an important role in determination of the product specificity.     

Novel Medium-Chain Prenyl Diphosphate Synthase from the Thermoacidophilic Archaeon Sulfolobus solfataricus

Two open reading frames which encode the homologues of (all-E) prenyl diphosphate synthase are found in the whole-genome sequence of Sulfolobus solfataricus, a thermoacidophilic archaeon. It has been suggested that one is a geranylgeranyl diphosphate synthase gene, but the specificity and biological significance of the enzyme encoded by the other have remained unclear. Thus, we isolated the latter by the PCR method, expressed the enzyme in Escherichia coli cells, purified it, and characterized it. The archaeal enzyme, 281 amino acids long, is highly thermostable and requires Mg(2+) and Triton X-100 for full activity. It catalyzes consecutive E-type condensations of isopentenyl diphosphate with an allylic substrate such as geranylgeranyl diphosphate and yields the medium-chain product hexaprenyl diphosphate. Despite such product specificity, phylogenetic analysis revealed that the archaeal medium-chain prenyl diphosphate synthase is distantly related to the other medium- and long-chain enzymes but is closely related to eucaryal short-chain enzymes.     

Site-directed mutagenesis of the conserved residues in component I of Bacillus subtilis heptaprenyl diphosphate synthase.

Heptaprenyl diphosphate synthase of Bacillus subtilis is composed of two dissociable heteromeric subunits, component I and component II. Component II has highly conserved regions typical of (E)-prenyl diphosphate synthases, but it shows no prenyltransferase activity alone unless it is combined with component I. Alignment of amino acid sequences for component I and the corresponding subunits of Bacillus stearothermophilus heptaprenyl diphosphate synthase and Micrococcus luteus B-P 26 hexaprenyl diphosphate synthase shows three regions of high similarity. To elucidate the role of these regions of component I during catalysis, 13 of the conserved amino acid residues in these regions were selected for substitution by site-directed mutagenesis. Kinetic studies indicated that substitutions of Val-93 with Gly, Leu-94 with Ser, and Tyr-104 with Ser resulted in 3-10-fold increases of K(m) values for the allylic substrate and 5-15-fold decreases of V(max) values compared to those of the wild-type enzyme. The three mutated enzymes, V93G, L94S, and Y104S, showed little binding affinity to the allylic substrate in the membrane filter assay. Furthermore, product analyses showed that D97A yielded shorter chain prenyl diphosphates as the main product, while Y103S gave the final product with a C(40) prenyl chain length. These results suggest that some of the conserved residues in region B of component I are involved in the binding of allylic substrate as well as determining the chain length of the enzymatic reaction product.     

A thermophilic cyanobacterium Synechococcus elongatus has three different Class I prenyltransferase genes

Prenyltransferases (prenyl diphosphate synthases), which are a broad group of enzymes that catalyze the consecutive condensation of homoallylic diphosphate of isopentenyl diphosphates (IPP, C₅) with allylic diphosphates to synthesize prenyl diphosphates of various chain lengths, have highly conserved regions in their amino acid sequences. Based on the above information, three prenyltransferase homologue genes were cloned from a thermophilic cyanobacterium, Synechococcus elongatus. Through analyses of the reaction products of the enzymes encoded by these genes, it was revealed that one encodes a thermolabile geranylgeranyl (C₂₀) diphosphate synthase, another encodes a farnesyl (C₁₅) diphosphate synthase whose optimal reaction temperature is 60 °C, and the third one encodes a prenyltransferase whose optimal reaction temperature is 75 °C. The last enzyme could catalyze the synthesis of five prenyl diphosphates of farnesyl, geranylgeranyl, geranylfarnesyl (C₂₅), hexaprenyl (C₃₀), and heptaprenyl (C₃₅) diphosphates from dimethylallyl (C₅) diphosphate, geranyl (C₂₀) diphosphate, or farnesyl diphosphate as the allylic substrates. The product specificity of this novel kind of enzyme varied according to the ratio of the allylic and homoallylic substrates. The situations of these three S. elongatus enzymes in a phylogenetic tree of prenyltransferases are discussed in comparison with a mesophilic cyanobacterium of Synechocystis PCC6803, whose complete genome has been reported by Kaneko et al. (1996).     

Stereochemical analysis of prenyltransferase reactions leading to (Z)- and (E)-polyprenyl chains

A feasible method was developed to determine the stereochemical direction of the C-C bond formation with respect to the face of the double bond of isopentenyl diphosphate in the prenyltransferase reactions. This method was applied to the reactions of undecaprenyl diphosphate synthase and heptaprenyl diphosphate synthase, which catalyze (Z)-prenyl chain elongation and (E)-prenyl chain elongation, respectively. In both cases, the C-C bond formation was found to take place at the si face of the double bond with elimination of one of the hydrogens of C-2 in a syn fashion.     

Chain elongation in the isoprenoid biosynthetic pathway

Isoprenyl diphosphate synthases catalyze addition of allylic diphosphate primers to the isoprene unit in isopentenyl diphosphate to produce polyisoprenoid diphosphates with well defined chain lengths. Phylogenetic correlations suggest that the synthases which catalyze formation of isoprenoid diphosphates with (E) double bonds have evolved from a common ancestor. X-ray crystallographic studies of farnesyl diphosphate synthase in conjunction with site-directed mutagenesis have provided important new information about the residues involved in binding and catalysis and the source of chain length selectivity for the enzymes that catalyze chain elongation.     

Polyprenyl phosphate biosynthesis in Mycobacterium tuberculosis and Mycobacterium smegmatis

Mycobacterium smegmatis has been shown to contain two forms of polyprenyl phosphate (Pol-P), while Mycobacterium tuberculosis contains only one. Utilizing subcellular fractions from M. smegmatis and M. tuberculosis, we show that Pol-P synthesis is different in these species. The specific activities of the prenyl diphosphate synthases in M. tuberculosis are 10- to 100-fold lower than those in M. smegmatis. In M. smegmatis decaprenyl diphosphate and heptaprenyl diphosphate were the main products synthesized in vitro, whereas in M. tuberculosis only decaprenyl diphosphate was synthesized. The data from both organisms suggest that geranyl diphosphate is the allylic substrate for two distinct prenyl diphosphate synthases, one located in the cell membrane that synthesizes omega,E,Z-farnesyl diphosphate and the other present in the cytosol that synthesizes omega,E,E,E-geranylgeranyl diphosphate. In M. smegmatis, the omega,E, Z-farnesyl diphosphate is utilized by a membrane-associated prenyl diphosphate synthase activity to generate decaprenyl diphosphate, and the omega,E,E,E-geranylgeranyl diphosphate is utilized by a membrane-associated activity for the synthesis of the heptaprenyl diphosphate. In M. tuberculosis, however, omega,E,E,E-geranylgeranyl diphosphate is not utilized for the synthesis of heptaprenyl diphosphate. Thus, the difference in the compositions of the Pol-P of M. smegmatis and M. tuberculosis can be attributed to distinct enzymatic differences between these two organisms.     

The product chain length determination mechanism of type II geranylgeranyl diphosphate synthase requires subunit interaction

The product chain length determination mechanism of type II geranylgeranyl diphosphate synthase from the bacterium, Pantoea ananatis, was studied. In most types of short-chain (all-E) prenyl diphosphate synthases, bulky amino acids at the fourth and/or fifth positions upstream from the first aspartate-rich motif play a primary role in the product determination mechanism. However, type II geranylgeranyl diphosphate synthase lacks such bulky amino acids at these positions. The second position upstream from the G(Q/E) motif has recently been shown to participate in the mechanism of chain length determination in type III geranylgeranyl diphosphate synthase. Amino acid substitutions adjacent to the residues upstream from the first aspartate-rich motif and from the G(Q/E) motif did not affect the chain length of the final product. Two amino acid insertion in the first aspartate-rich motif, which is typically found in bacterial enzymes, is thought to be involved in the product determination mechanism. However, deletion mutation of the insertion had no effect on product chain length. Thus, based on the structures of homologous enzymes, a new line of mutants was constructed in which bulky amino acids in the alpha-helix located at the expected subunit interface were replaced with alanine. Two mutants gave products with longer chain lengths, suggesting that type II geranylgeranyl diphosphate synthase utilizes an unexpected mechanism of chain length determination, which requires subunit interaction in the homooligomeric enzyme. This possibility is strongly supported by the recently determined crystal structure of plant type II geranylgeranyl diphosphate synthase.     

Geranyl diphosphate synthase from Abies grandis: cDNA isolation,functional expression,and characterization

Geranyl diphosphate synthase catalyzes the condensation of dimethylallyl diphosphate and isopentenyl diphosphate to generate geranyl diphosphate, the essential precursor of monoterpene biosynthesis. Using geranylgeranyl diphosphate synthase from Taxus canadensis as a hybridization probe, four full length cDNA clones, sharing high sequence identity to each other (>69%) and to the Taxus geranylgeranyl diphosphate synthase (>66%), were isolated from a grand fir (Abies grandis) cDNA library. When expressed in Escherichia coli, three of the recombinant enzymes produced geranyl diphosphate and one produced geranylgeranyl diphosphate as the dominant product when supplied with isopentenyl diphosphate and dimethylallyl diphosphate as cosubstrates. One enzyme (AgGPPS2) was confirmed as a specific geranyl diphosphate synthase, in that it accepted only dimethylallyl diphosphate as the allylic cosubstrate and it produced exclusively geranyl diphosphate as product, with a k(cat) of 1.8s(-1). Gel filtration experiments performed on the recombinant geranyl diphosphate synthases, in which the plastidial targeting sequences had been deleted, revealed that these enzymes are homodimers similar to other short-chain prenyltransferases but different from the heterotetrameric geranyl diphosphate synthase of mint.     

Chain-length determination mechanism of isoprenyl diphosphate synthases and implications for molecular evolution.

In the synthesis of isoprenoids, isoprenyl diphosphate synthases catalyze the consecutive condensation of isopentenyl diphosphate with allylic diphosphates to produce a variety of prenyl diphosphates with well-defined chain lengths. Site-directed mutagenesis in conjunction with X-ray crystallographic studies have identified specific amino acid residues responsible for chain-length determination. Simple combinations of these residues within a characteristic motif are not only sufficient to confer product specificities to all isoprenyl diphosphate synthases but represent structural features that reflect the enzyme family's evolutionary course.     

Enzymes encoded by the farnesyl diphosphate synthase gene family in the Big Sagebrush Artemisia tridentata ssp. spiciformis

Farnesyl diphosphate synthase catalyzes the sequential head-to-tail condensation of two molecules of isopentenyl diphosphate with dimethylallyl diphosphate. In plants the presence of farnesyl diphosphate synthase isozymes offers the possibility of differential regulation. Three full-length cDNAs encoding putative isoprenoid synthases, FDS-1, FDS-2, and FDS-5, with greater than 89% similarity were isolated from a Big Sagebrush Artemisia tridentata cDNA library using a three-step polymerase chain reaction protocol. One of the open reading frames, FDS-5, encoded a protein with an N-terminal amino acid extension that was identified as a plastidial targeting peptide. Recombinant histidine-tagged versions of three proteins were purified, and their enzymatic properties were characterized. FDS-1 and FDS-2 synthesized farnesyl diphosphate as the final chain elongation product, but their kinetic behavior varied. FDS-1 prefers geranyl diphosphate over dimethylallyl diphosphate as an allylic substrate and is active at acidic pH values compared with FDS-2. In contrast, FDS-5 synthesized two irregular monoterpenoids, chrysanthemyl diphosphate and lavandulyl diphosphate, when incubated with dimethylallyl diphosphate and an additional product, the regular monoterpene geranyl diphosphate, when incubated with isopentenyl diphosphate and dimethylallyl diphosphate. Specific cellular functions are proposed for each of the three enzymes, and a scenario for evolution of isoprenyl synthases in plants is presented.     

Protein design of geranyl diphosphate synthase. Structural features that define the product specificities of prenyltransferases.

Geranyl diphosphate synthase catalyzes the condensation of isopentenyl diphosphate with dimethylallyl diphosphate to give a C(10) compound, geranyl diphosphate, which is a precursor of all monoterpenoids. However, the gene has not been isolated from any organisms. To examine the possibility that geranyl diphosphate synthase has evolved from a common ancestor of the prenyltransferase family and to predict the active site structure, we tried to convert Bacillus stearothermophilus farnesyl diphosphate synthase to geranyl diphosphate synthase, according to our previous findings. Several mutated farnesyl diphosphate synthases that have single amino acid substitutions before the first aspartate-rich motif were constructed. A mutated enzyme that has the replacement of serine by phenylalanine at the fourth position before the motif exclusively produced geranyl diphosphate when dimethylallyl diphosphate was used as the primer, and hardly accepted geranyl diphosphate as a primer, indicating that this mutation causes the conversion to geranyl diphosphate synthase. This result supports the idea that the product specificities of all members of the E-prenyltransferase family are mainly defined by a few structural features: the amino acids at the fourth position and the fifth position before the first aspartate-rich motif, and the insertion of two amino acids in the motif. This suggests that natural geranyl diphosphate synthases might have an active site structure similar to that of the mutated enzyme.     

The role of ERG20 gene (encoding yeast farnesyl diphosphate synthase) mutation in long dolichol formation. Molecular modeling of FPP synthase

The yeast Saccharomyces cerevisiae strain LB332 bearing a mutation in the ERG20 gene encoding farnesyl diphosphate synthase (FPPS) synthesizes significantly longer dolichols than the wild type strain FL100 (14-31 and 14-19 isoprene units, respectively). The measurement of the short chain prenyl alcohols excreted into the medium shows that increased amounts of geraniol, dimethylallyl and isopentenyl alcohols but not farnesol are synthesized by the mutant strain. The wild type FPPS synthesizes farnesyl diphosphate (FPP) as the only product. The K197E substitution, as opposed to F112A/F113S in avian FPPS, does not change product specificity. Consequently, the possibility that mutated yeast FPPS synthesizes longer polyprenols is unlikely. This is supported by additional evidence such as in vitro analysis of the mutated FPPS products and molecular modeling. We suggest that formation of longer dolichols in vivo is the result of a change in the isopentenyl diphosphate/farnesyl diphosphate ratio caused by the erg20 mutation which in turn affects the activity of cis-prenyltransferase.     

Manipulation of prenyl chain length determination mechanism of cis-prenyltransferases

The carbon backbones of Z,E-mixed isoprenoids are synthesized by sequential cis-condensation of isopentenyl diphosphate (IPP) and an allylic diphosphate through actions of a series of enzymes called cis-prenyltransferases. Recent molecular analyses of Micrococcus luteus B-P 26 undecaprenyl diphosphate (UPP, C55) synthase [Fujihashi M, Zhang Y-W, Higuchi Y, Li X-Y, Koyama T & Miki K (2001) Proc Natl Acad Sci USA98, 4337-4342.] showed that not only the primary structure but also the crystal structure of cis-prenyltransferases were totally different from those of trans-prenyltransferases. Although many studies on structure-function relationships of cis-prenyltransferases have been reported, regulation mechanisms for the ultimate prenyl chain length have not yet been elucidated. We report here that the ultimate chain length of prenyl products can be controlled through structural manipulation of UPP synthase of M. luteus B-P 26, based on comparisons between structures of various cis-prenyltransferases. Replacements of Ala72, Phe73, and Trp78, which are located in the proximity of the substrate binding site, with Leu--as in Z,E-farnesyl diphosphate (C15) synthase--resulted in shorter ultimate products with C(20-35). Additional mutation of F223H resulted in even shorter products. On the other hand, insertion of charged residues originating from long-chain cis-prenyltransferases into helix-3, which participates in constitution of the large hydrophobic cleft, resulted in lengthening of the ultimate product chain length, leading to C(60-75). These results helped us understand reaction mechanisms of cis-prenyltransferase including regulation of the ultimate prenyl chain-length.     

Substrate specificities of wild and mutated farnesyl diphosphate synthases from Bacillus stearothermophilus with artificial substrates

To determine the substrate specificities of wild and mutated types of farnesyl diphosphate (FPP) synthases from Bacillus stearothermophilus, we examined the reactivities of 8-hydroxygeranyl diphosphate (HOGPP) and 8-methoxygeranyl diphosphate (CH(3)OGPP) as allylic substrate homologs. The wild-type FPP synthase reaction of HOGPP (and CH(3)OGPP) with isopentenyl diphosphate (IPP) gave hydroxyfarnesyl- (and methoxyfarnesyl-) diphosphates that stopped at the first stage of condensation. On the other hand, with mutated type FPP synthase (Y81S), the former gave hydroxygeranylgeranyl diphosphate as the main double-condensation product together with hydroxyfarnesyl diphosphate as a single-condensation product and a small amount of hydroxygeranylfarnesyl diphosphate as a triple-condensation product. Moreover, the latter gave a double-condensation product, methoxygeranylgeranyl diphosphate, as the main product and only a trace of methoxyfarnesyl diphosphate was obtained.