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)