Identification, characterization, and expression of diacylgylcerol acyltransferase type-1 from Chlorella vulgaris

authored by: Linda Kirchner, Alison Wirshing, Lutfiye Kurt, Thomas Reinard, James Glick, Erin J. Cram, Hans-Jörg Jacobsen, Carolyn W.T. Lee-Parsons
Abstract: The green microalga Chlorella vulgaris can be induced to rapidly accumulate oil (40% by dry weight) with a biodiesel profile that is high in saturated and monounsaturated fatty acids. In this study, we sequenced the diacylglycerol acyltransferase type-1 from C. vulgaris (CvuDGAT1), which catalyzes the last step in triacylglycerol (TAG) biosynthesis, and characterized this protein using bioinformatics and functional expression assays in a yeast mutant. The CvuDGAT1 protein (460aa) shares motifs characteristic of other plant and microalga DGAT1s, including the binding domains for the acyl-CoA and diacylglycerol substrates and the putative active site. In addition, we report the first putative tertiary structure of DGAT1. This model shows that CvuDGAT1 is integrated into the ER membrane and predicts the proximity of the substrate-binding domains and the active site, despite being widely separated in the protein sequence. We also demonstrate CvuDGAT1's function in TAG biosynthesis by expressing the gene and restoring oil levels in a non-oil-producing yeast mutant. Interestingly, unlike Chlamydomonas reinhardtii, the CvuDGAT1 gene is constitutively expressed at high levels and may contribute to this species' ability to accumulate high levels of oil (i.e. 40% by dry weight).
Organisation(s): Institute of Plant Genetics
Section Plant Biotechnology
External Organisation(s): Northeastern University
Type: Article
Journal: Algal Research
Volume: 13
Pages: 167-181
No. of pages: 15
ISSN: 2211-9264
Publication date: 01.2016
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Agronomy and Crop Science
Electronic version(s): https://doi.org/10.1016/j.algal.2015.10.017 (Access: Closed)
https://doi.org/10.1016/j.algal.2016.02.010 (Access: Closed)