an Arabidopsis mrn1 knock-out mutant shows round-shaped leaves and late flowering is isolated under long-day conditions. The late-flowering phenotype is much more severe under short-day conditions than under longday conditions. The mrn1 mutant displays aberrant seed morphology, a low germination rate, and root growth retardation. Mrn1 mutant shows a delayed embryo development
the OSC MRN1 from Arabidopsis thaliana catalyzes the formation of the seco-triterpene marneral via an unusual chair-boat substrate conformation, resulting in a further atypical, monocyclic triterpenoid structure, LC-MS analysis
2,3-oxidosqualene production is implemented and subsequently combined with different cyclization reactions catalyzed by the representative oxidosqualene cyclases CAS1 (cycloartenol synthase), LUP1 (lupeol synthase), THAS1 (thalianol synthase) and MRN1 (marneral synthase), derived from model plant Arabidopsis thaliana, in the two alternative hosts for biosynthesis of cyclic plant triterpenes, the metabolically versatile photosynthetic alpha-proteobacterium Rhodobacter capsulatus strain SB1003 and cyanobacterium Synechocystis sp. PCC 6803, triterpene pathway design, overview. While successful accumulation of 2,3-oxidosqualene can be detected by LC-MS analysis in both hosts, cyclase expression results in differential production profiles. CAS1 catalyzes conversion to only cycloartenol, but expression of LUP1 yields lupeol and a triterpenoid matching an oxidation product of lupeol, in both hosts. In contrast, THAS1 expression does not lead to cyclic product formation in either host, whereas MRN1-dependent production of marnerol and hydroxymarnerol is observed in Synechocystis but not in Rhodobacter capsulatus. 2,3-Oxidosqualene cyclization in heterologous phototrophic bacteria is basically feasible but efficient conversion depends on both the respective cyclase enzyme and individual host properties
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
gene MRN1, recombinant expression in Rhodobacter capsulatus strain SB1003. and Synechocystis sp. PCC 6803 using promoters Pnif and PcoaT, coexpression with CAS1, LUP1, and THAS1. Subcloning in Saccharomyces cerevisiae strain GIL77, both marnerol and the putative hydroxymarnerol are detected in the reference yeast strain expressing MRN1. Isolation of triterpenes, while cycloartenol and lupeol represent typical plant triterpenes with tetracyclic plant sterol and pentacyclic plant triterpene scaffolds, respectively, thalianol and marneral exhibit more unusual tri- and monocyclic structures