Research
| Title： | Microalgal plastidial lysophosphatidic acid acyltransferase interacts with upstream glycerol-3-phosphate acyltransferase and defines its substrate selectivity via the two transmembrane domains |
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| First author： | Huang, Linfei; Yu, Lihua; Li, Zhongze; Li, Yanhua; Yoon, Kang-sup; Hu, Qiang; Yuan, Li; Han, Danxiang |
| Journal： | ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS |
| Years： | 2020 |
| DOI： | 10.1016/j.algal.2019.101758 |
| Abstract： | The plastidial lysophosphatidic acid acyltransferase of the unicellular green alga Chlamydomonas reinhardtii (CrLPAAT1) is a key enzyme involved in triacylglycerol biosynthesis. However, research on the biochemical characteristics of CrLPAAT1 has been impeded by its membrane-bound nature. In this study, the recombinant CrLPAAT1 was purified in a soluble form and was utilized for comprehensive biochemical characterization. The recombinant CrLPAAT1 favors the conditions of pH 6.5-7.5, 30 degrees C and the presence of magnesium ion in vitro. Similar with the CrLPAAT1 associated with the membranes, the purified CrLPAAT1 prefers to utilize C16:0-CoA over other acyl donors, whereas it showed broader substrate selectivity than the membrane-bound enzyme. By comparing the wild-type CrLPAAT1 and a transmembrane domain-truncated enzyme, it was uncovered in this study that the two transmembrane domains of CrLPAAT1 are involved in shaping its substrate preference for C16:0-CoA. Additionally, CrLPAAT1 was found to be interacting with the water-soluble plastidial glycerol-3-phosphate acyltransferase (CrGAPTcl) via its two transmembrane domains in vitro. The interaction between CrLPAAT1 and CrGPATcl can be negatively regulated by both the acyl-CoAs and lysophosphatidic acid in a dosage-dependent manner. Such a regulation pattern may represent a novel mechanism adopted by algal cells to control lipid metabolism homeostasis under various environmental conditions. |
