Jallouli Raida, Othman Houcemeddine, Amara Sawsan, Parsiegla Goetz, Carriere Frédéric, Srairi-Abid Najet, Gargouri Youssef, Bezzine Sofiane
Univertsity of Sfax, Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS route de Soukra, BPW 3038 Sfax, Tunisia.
Université Tunis-ElManar, Institut Pasteur de Tunis, Laboratoire des Venins et Biomolécules Thérapeutiques LR11IPT08, Tunis 1002, Tunisia.
Biochim Biophys Acta. 2015 Mar;1851(3):282-9. doi: 10.1016/j.bbalip.2014.12.010. Epub 2014 Dec 18.
The purified (phospho)lipase of Fusarium solani (FSL), was known to be active on both triglycerides and phospholipids. This study aimed at assessing the potential of this enzyme in hydrolyzing galactolipids. FSL was found to hydrolyze at high rates of synthetic medium chains monogalactosyldiacylglycerol (4658±146U/mg on DiC8-MGDG) and digalactosyldiacylglycerol (3785±83U/mg on DiC8-DGDG) and natural long chain monogalactosyldiacylglycerol extracted from leek leaves (991±85U/mg). It is the microbial enzyme with the highest activity on galactolipids identified so far with a level of activity comparable to that of pancreatic lipase-related protein 2. FSL maximum activity on galactolipids was measured at pH8. The analysis of the hydrolysis product of natural MGDG from leek showed that FSL hydrolyzes preferentially the ester bond at the sn-1 position of galactolipids. To investigate the structure-activity relationships of FSL, a 3D model of this enzyme was built. In silico docking of medium chains MGDG and DGDG and phospholipid in the active site of FSL reveals structural solutions which are in concordance with in vitro tests.
茄病镰刀菌（FSL）的纯化（磷酸化）脂肪酶已知对甘油三酯和磷脂均有活性。本研究旨在评估该酶水解半乳糖脂的潜力。发现FSL能高效水解合成中链单半乳糖基二酰基甘油（对二辛酰单半乳糖基二酰基甘油的水解活性为4658±146U/mg）和二半乳糖基二酰基甘油（对二辛酰二半乳糖基二酰基甘油的水解活性为3785±83U/mg）以及从韭菜叶中提取的天然长链单半乳糖基二酰基甘油（991±85U/mg）。它是目前已鉴定出的对半乳糖脂活性最高的微生物酶，其活性水平与胰腺脂肪酶相关蛋白2相当。FSL对半乳糖脂的最大活性在pH8时测得。对韭菜中天然单半乳糖基二酰基甘油水解产物的分析表明，FSL优先水解半乳糖脂sn-1位的酯键。为了研究FSL的构效关系，构建了该酶的三维模型。在计算机模拟中，中链单半乳糖基二酰基甘油、二半乳糖基二酰基甘油和磷脂在FSL活性位点的对接揭示了与体外试验一致的结构解析。
