The galactolipase activity of Fusarium solani (phospho)lipase

Raida Jallouli, Houcemeddine Othman, Sawsan Amara, Goetz Parsiegla, Frédéric Carriere, Najet Srairi-abid, Youssef Gargouri, Sofiane Bezzine

Univertsity of Sfax, Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS route de Soukra, BPW 3038 Sfax, Tunisia.

Abstract

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 ± 146 U/mg on DiC8-MGDG) and digalactosyldiacylglycerol (3785 ± 83 U/mg on DiC8-DGDG) and natural long chain monogalactosyldiacylglycerol extracted from leek leaves (991 ± 85 U/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 pH 8. 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.

Keywords: Fusarium solani (phospho)lipase; Galactolipase; Galactolipid; Leek; In silico docking.