title: Identification of a novel phospholipase D with high transphosphatidylation activity and its application in synthesis of phosphatidylserine and DHA-phosphatidylserine.
abstract: Phosphatidylserine (PS) and docosahexaenoic acid-phosphatidylserine (DHA-PS) have significant nutritional and biological functions, which are extensively used in functional food industries. Phospholipase D (PLD)-mediated transphosphatidylation of phosphatidylcholine (PC) or DHA-PC with l-serine, is an effective method for PS and DHA-PS preparation. However, because of the hydrolysis activity of PLD, PC and DHA-PC would be converted to the undesirable byproduct, phosphatidic acid (PA) and DHA-PA. In this study, a novel phospholipase D (PLDa2) was firstly cloned from Acinetobacter radioresistens a2 with high transphosphatidylation activity and no hydrolysis activity. In the PLD-catalyzed synthesis process (12h), both the transphosphatidylation conversion rate and selectivity of PS and DHA-PS were about 100%, which is the only PLD enzyme reported with this superiority up till now. In comparison with the majority of other known PLDs, PLDa2exerted the highest activity at neutral pH, and it was stable from pH 4.0 to pH 9.0. In addition, PLDa2had excellent thermal stability, with an optimum reaction temperature of 40°C and keeping more than 80% activity from 20°C to 60°C. The high catalytic selectivity mechanism of PLDa2was explained by utilizing homology modeling, two-step docking, and binding energy and conformation analysis. PLDa2ensured a stable supply of the biocatalyst with its most preponderant transphosphatidylation activity and PS selectivity, and had great potential in phospholipids industrial production.
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China. Electronic address: xzhmao@ouc.edu.cn.
authors.forename: Xiangzhao
authors.initials: X
authors.lastname: Mao
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Yongqian
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Fan
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Han
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China; School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, PR China.
authors.forename: Lujia
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, PR China. Electronic address: xuech@ouc.edu.cn.
authors.forename: Changhu
authors.initials: C
authors.lastname: Xue
mesh_terms: D000150:Acinetobacter / Q000201:enzymology / Q000235:genetics; D004281:Docosahexaenoic Acids / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D062105:Molecular Docking Simulation; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism*; D010739:Phospholipase D / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D010718:Phosphatidylserines; D011994:Recombinant Proteins; D004281:Docosahexaenoic Acids; D010739:Phospholipase D
keywords: Acinetobacter radioresistens; Docosahexaenoic acid-phosphatidylserine; Homology modeling; Phosphatidylserine; Phospholipase D; Transphosphatidylation activity