Identification and Quantification of Cyclolinopeptides in Five Flaxseed Cultivars

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1021/jf301847uJournal of Agricultural and Food Chemistry, 60, 35, pp. 8571-8579, 2012-08-16 Identification and quantification of Cyclolinopeptides in five flaxseed cultivars Gui, Bo; Shim, Youn Young; Datla, Raju S. S.; Covello, Patrick S.; Stone, Sandra L.; Reaney, Martin J. T. ABSTRACT: Cyclolinopeptides are a group of naturally occurring hydrophobic cyclic peptides found in flaxseed and flax oil that have immunosuppressive activity. This study describes the measurement of flaxseed cyclolinopeptide concentrations using an internal standard HPLC method. In addition, the concentration of cyclolinopeptides in the seed of Canadian flax cultivars grown at two locations over two years is reported. The data are consistent with the formation of flaxseed cyclolinopeptides from two ribosome-derived precursors. Each precursor protein includes the sequences corresponding to three cyclolinopeptides from which those cyclolinopeptides are presumably derived by precursor processing. The concentrations of cyclolinopeptides C and E, which are encoded by the same gene sequence, are highly correlated, and the concentrations of cyclolinopeptides D, F, and G, which are encoded by a second gene sequence, are also highly correlated. The strong correlation between the cyclolinopeptides arising from the same gene may prove to be important in understanding how peptide concentration is controlled. Additional research may lead to approaches to improve flax either as a platform for peptide production or as a source of oil with improved drying properties and flavor. Identification and Quantification of Cyclolinopeptides in

Characterization of the macrocyclase involved in the biosynthesis of RiPP cyclic peptides in plants

“…Additionally, the transamidative protease involved in the biosynthesis of amatoxin (GmPOPB) was initially shown to have a similar K M value and a 100-fold faster rate (k cat of 5.7·s −1 ) (30), whereas more extensive kinetic analysis indicated a K M about 75-fold higher and a k cat approximately 4-fold faster than PCY1 (36). [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] substrate (m/z = 993.2, z = 2; blue trace), and the presegetalin A1 [20][21][22][23][24][25][26][27][28][29][30][31][32] by-product (m/z = 688.5, z = 2; purple trace) are shown as indicated. The wild-type PCY1 used most of the presegetalin A1 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]…”

“…As presegetalin A1 [27][28][29][30][31][32] binding induces closure of the PCY1 structure, addition of exogenous peptide would be expected to inhibit productive turnover of the presegetalin A1 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] substrate. We tested this hypothesis using a 1-h end-point reaction of PCY1 incubated with 30 μM of substrate in the presence of stoichiometric and 10-fold excess of the presegetalin A1 [20][21][22][23][24][25][26][27][28][29][30][31][32] linker+follower peptide product, as well as 100-fold excess of the presegetalin A1 [27][28][29][30][31][32] follower peptide (SI Appendix, Fig.…”

“…Similar patterns of conservation are observed for the precursors of other cyclic peptides including cyanobactins (31) and amatoxins (19,32). Alanine scanning mutational analysis of presegetalin A1 demonstrates that the necessary elements for substrate recognition by PCY1 reside solely in the 12-residue follower sequence (hereafter, presegetalin A1 [20][21][22][23][24][25][26][27][28][29][30][31][32]) that is excised during the formation of the macrocyclic product (27). Notably, PCY1 can accept a range of substrates leading to rings of different sizes as this single enzyme is capable of processing almost all of the orbitides that are observed in S. vaccaria.…”

“…13 residues (termed presegetalin A1 [20][21][22][23][24][25][26][27][28][29][30][31][32]), with the concomitant macrocyclization of the remaining N-terminal six residues to yield the cyclo[GVPVWA] segetalin A product (Fig. 1B).…”

“…1A) (20). Since then, over 168 Caryophyllaceae-like nonredundant orbitides have been identified, and encoding sequences have been confirmed in Annonaceae, Rutaceae, Euphorbiaceae, and Linaceae (21). Many orbitides demonstrate biological activities including antimalarial (22), vasodilatory (23), immunomodulating (24), and xenoestrogenic activities (25).…”