title: Two Clades of Type-1 Brassica napus Diacylglycerol Acyltransferase Exhibit Differences in Acyl-CoA Preference.
abstract: Diacylglycerol acyltransferase (DGAT) catalyzes the acyl-CoA-dependent acylation of sn-1, 2-diacylglycerol to produce triacylglycerol, which is the main component of the seed oil of Brassica oilseed species. Phylogenetic analysis of the amino acid sequences encoded by four transcriptionally active DGAT1 genes from Brassica napus suggests that the gene forms diverged over time into two clades (I and II), with representative members in each genome (A and C). The majority of the amino acid sequence differences in these forms of DGAT1, however, reside outside of motifs suggested to be involved in catalysis. Despite this, the clade II enzymes displayed a significantly enhanced preference for linoleoyl-CoA when assessed using in-vitro enzyme assays with yeast microsomes containing recombinant enzyme forms. These findings contribute to our understanding of triacylglycerol biosynthesis in B. napus, and may advance our ability to engineer DGAT1s with desired substrate selectivity properties.
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Greer
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
authors.forename: Xue
authors.initials: X
authors.lastname: Pan
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada. randall.weselake@ualberta.ca.
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Weselake
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism*; D000215:Acylation; D000595:Amino Acid Sequence; D029688:Brassica napus / Q000145:classification / Q000201:enzymology*; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics* / Q000378:metabolism; D018745:Genome, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides
chemical_list: D000214:Acyl Coenzyme A; D010940:Plant Proteins; D014280:Triglycerides; D051048:Diacylglycerol O-Acyltransferase
keywords: DGAT; MBOAT; Oilseed rape; Substrate specificity; Triacylglycerol biosynthesis