Farnesyl dlphosphate synthase （FPS; EC 2.5.1.10） catalyzes the production of 15-carbon farnesyl dlphosphate which Is a branch-point Intermediate for many terpenoids. This reaction Is considered to be a ratelimiting ...Farnesyl dlphosphate synthase （FPS; EC 2.5.1.10） catalyzes the production of 15-carbon farnesyl dlphosphate which Is a branch-point Intermediate for many terpenoids. This reaction Is considered to be a ratelimiting step In terpenold biosynthesis. Here we report for the first time the cloning of a new full-length cDNA encoding farnesyl dlphosphate synthase from a gymnosperm plant species, Taxus media Rehder, designated as TmFPS1. The full-length cDNA of TmFPS1 （GenBank accession number： AY461811） was 1 464 bp with a 1 056-bp open reading frame encoding a 351-amino acid polypeptlde with a calculated molecular weight of 40.3 kDa and a theoretical pl of 5.07. Biolnformatlc analysis revealed that TmFPS1 contained all five conserved domains of prenyltransferases, and showed homology to other FPSs of plant origin. Phylogenetlc analysis showed that farnesyl dlphosphate synthases can be divided Into two groups： one of prokaryotic origin and the other of eukaryotic origin. TmFPS1 was grouped with FPSs of plant origin. Homologybased structural modeling showed that TmFPS1 had the typical spatial structure of FPS, whose most prominent structural feature Is the arrangement of 13 core helices around a large central cavity In which the catalytic reaction takes place. Our blolnformatic analysis strongly suggests that TmFPS1 is a functional gene. Southern blot analysis revealed that TmFPS1 belongs to a small FPSgene family in T. media. Northern blot analysis indicated that TmFPS1 is expressed in all tested tissues, Including the needles, stems and roots of T. media. Subsequently, functional complementatlon with TmFPS1 in a FPS-deflclent mutant yeast demonstrated that TmFPS1 did encode farnesyl dlphosphate synthase, which rescued the yeast mutant. This study will be helpful In future Investigations aiming at understanding the detailed role of FPS In terpenold biosynthesis flux control at the molecular genetic level.展开更多
Puccinellia tenuiflora is a typical salt-excluding halophytic grass with strong salt-tolerance, which enhances tolerance by restricting Na^+influx as well as having a strong selectivity for K^+ over Na^+. The HAK5 K^+...Puccinellia tenuiflora is a typical salt-excluding halophytic grass with strong salt-tolerance, which enhances tolerance by restricting Na^+influx as well as having a strong selectivity for K^+ over Na^+. The HAK5 K^+ transporters generally modulate effective K^+acquisition in plants, especially under low K^+ condition. In this study,Pt HAK5 from P. tenuiflora was isolated by RT-PCR and characterized using yeast complementation. The results showed Pt HAK5 consisted of 784 amino acids and shared over 80% homology with the identified high-affinity K^+ transporter HAK5 from other higher plants. The expression of PtHAK5 rescued the K^+ -uptake-defective phenotype of yeast strain CY162. In conclusion, PtHAK5 is a candidate for mediating high-affinity K^+ uptake under low K^+ conditions.展开更多
基金Supported by the Hi-Tech Research and Development(863) Program of China,and the National Natural Science Foundation of China(30500303)
文摘Farnesyl dlphosphate synthase （FPS; EC 2.5.1.10） catalyzes the production of 15-carbon farnesyl dlphosphate which Is a branch-point Intermediate for many terpenoids. This reaction Is considered to be a ratelimiting step In terpenold biosynthesis. Here we report for the first time the cloning of a new full-length cDNA encoding farnesyl dlphosphate synthase from a gymnosperm plant species, Taxus media Rehder, designated as TmFPS1. The full-length cDNA of TmFPS1 （GenBank accession number： AY461811） was 1 464 bp with a 1 056-bp open reading frame encoding a 351-amino acid polypeptlde with a calculated molecular weight of 40.3 kDa and a theoretical pl of 5.07. Biolnformatlc analysis revealed that TmFPS1 contained all five conserved domains of prenyltransferases, and showed homology to other FPSs of plant origin. Phylogenetlc analysis showed that farnesyl dlphosphate synthases can be divided Into two groups： one of prokaryotic origin and the other of eukaryotic origin. TmFPS1 was grouped with FPSs of plant origin. Homologybased structural modeling showed that TmFPS1 had the typical spatial structure of FPS, whose most prominent structural feature Is the arrangement of 13 core helices around a large central cavity In which the catalytic reaction takes place. Our blolnformatic analysis strongly suggests that TmFPS1 is a functional gene. Southern blot analysis revealed that TmFPS1 belongs to a small FPSgene family in T. media. Northern blot analysis indicated that TmFPS1 is expressed in all tested tissues, Including the needles, stems and roots of T. media. Subsequently, functional complementatlon with TmFPS1 in a FPS-deflclent mutant yeast demonstrated that TmFPS1 did encode farnesyl dlphosphate synthase, which rescued the yeast mutant. This study will be helpful In future Investigations aiming at understanding the detailed role of FPS In terpenold biosynthesis flux control at the molecular genetic level.
基金supported by the National Natural Science Foundation of China (31730093, 31470503)
文摘Puccinellia tenuiflora is a typical salt-excluding halophytic grass with strong salt-tolerance, which enhances tolerance by restricting Na^+influx as well as having a strong selectivity for K^+ over Na^+. The HAK5 K^+ transporters generally modulate effective K^+acquisition in plants, especially under low K^+ condition. In this study,Pt HAK5 from P. tenuiflora was isolated by RT-PCR and characterized using yeast complementation. The results showed Pt HAK5 consisted of 784 amino acids and shared over 80% homology with the identified high-affinity K^+ transporter HAK5 from other higher plants. The expression of PtHAK5 rescued the K^+ -uptake-defective phenotype of yeast strain CY162. In conclusion, PtHAK5 is a candidate for mediating high-affinity K^+ uptake under low K^+ conditions.
