Differences in chain length distribution of inulin from Cynara scolymus and Helianthus tuberosus are reflected in a transient plant expression system using the respective 1-FFT cDNAs.
A newly isolated cDNA clone, Cy3, encoding the fructan fructan 1-fructosyltransferase (1-FFT) from artichoke was expressed using tobacco protoplasts as expression system. Analysis of the inulin molecules synthesized upon incubation of protoplast extracts with a mixture of oligofructans (DP3-5) shows the production of inulins with a degree of polymerization (DP) of up to 23, whereas parallel experiments performed using a 1-FFT cDNA from Jerusalem artichoke led to the production of fructans with a DP of up to only 12. The results of in vitro fructan synthesis catalyzed by transiently expressed enzymes therefore reflect the difference of in vivo fructan composition of Jerusalem artichoke (M(DP) = 8-10) and artichoke (M(DP) = 65). These data suggest that the fructan pattern in a given species is mainly defined by the enzymatic characteristics of 1-FFT.
Hellwege
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EM
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Golm, Germany. hellwege@mpimp-golm-mpg.de
Raap
M
M
Gritscher
D
D
Willmitzer
L
L
Heyer
A G
AG
D000595:Amino Acid Sequence; D005630:Fructans / Q000032:analysis / Q000096:biosynthesis; D006368:Helianthus / Q000201:enzymology* / Q000235:genetics; D007444:Inulin / Q000737:chemistry*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D010947:Plants, Toxic; D011523:Protoplasts / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics; D014170:Transformation, Genetic
D005630:Fructans; D010940:Plant Proteins; D007444:Inulin