Jensen K.,Copenhagen University |
Jensen K.,Research Center Pro Active Plants |
Osmani S.A.,Copenhagen University |
Osmani S.A.,Research Center Pro Active Plants |
And 6 more authors.
Phytochemistry | Year: 2011
Formation of metabolons (macromolecular enzyme complexes) facilitates the channelling of substrates in biosynthetic pathways. Metabolon formation is a dynamic process in which transient structures mediated by weak protein-protein interactions are formed. In Sorghum, the cyanogenic glucoside dhurrin is derived from l-tyrosine in a pathway involving the two cytochromes P450 (CYPs) CYP79A1 and CYP71E1, a glucosyltransferase (UGT85B1), and the redox partner NADPH-dependent cytochrome P450 reductase (CPR). Experimental evidence suggests that the enzymes of this pathway form a metabolon. Homology modeling of the three membrane bound proteins was carried out using the Sybyl software and available relevant crystal structures. Residues involved in tight positioning of the substrates and intermediates in the active sites of CYP79A1 and CYP71E1 were identified. In both CYPs, hydrophobic surface domains close to the N-terminal trans-membrane anchor and between the F′ and G helices were identified as involved in membrane anchoring. The proximal surface of both CYPs showed positively charged patches complementary to a negatively charged bulge on CPR carrying the FMN domain. A patch of surface exposed, positively charged amino acid residues positioned on the opposite face of the membrane anchor was identified in CYP71E1 and might be involved in binding UGT85B1 via a hypervariable negatively charged loop in this protein. © 2011 Elsevier Ltd. All rights reserved.
Sonderby I.E.,Research Center Pro Active Plants |
Geu-Flores F.,Research Center Pro Active Plants |
Halkier B.A.,Research Center Pro Active Plants
Trends in Plant Science | Year: 2010
Glucosinolates are sulfur-rich secondary metabolites characteristic of the Brassicales order with important biological and economic roles in plant defense and human nutrition. Application of systems biology tools continues to identify genes involved in the biosynthesis of glucosinolates. Recent progress includes genes in all three phases of the pathway, i.e. side-chain elongation of precursor amino acids, formation of the core glucosinolate structure and side-chain decoration. Major breakthroughs include the ability to produce glucosinolates in Nicotiana benthamiana, the finding that specific glucosinolates play a key role in Arabidopsis innate immune response, and a better understanding of the link between primary sulfur metabolism and glucosinolate biosynthesis. © 2010 Elsevier Ltd. All rights reserved.