Omega fatty acids are recognized as key nutrients for healthier ageing. Lipases are used to release ω-3 fatty acids from oils for preparing enriched ω-3 fatty acid supplements. However, use of lipases in enrichment of ω-3 fatty acids is limited due to their insufficient specificity for ω-3 fatty acids. In this study use of phospholipase A1 (PLA1), which possesses both sn-1 specific activity on phospholipids and lipase activity, was explored for hydrolysis of ω-3 fatty acids from anchovy oil. Substrate specificity of PLA1 from Thermomyces lenuginosus was initially tested with synthetic p-nitrophenyl esters along with a lipase from Bacillus subtilis (BSL), as a lipase control. Gas chromatographic characterization of the hydrolysate obtained upon treatment of anchovy oil with these enzymes indicated a selective retention of ω-3 fatty acids in the triglyceride fraction by PLA1 and not by BSL. 13C NMR spectroscopy based position analysis of fatty acids in enzyme treated and untreated samples indicated that PLA1 preferably retained ω-3 fatty acids in oil, while saturated fatty acids were hydrolysed irrespective of their position. Hydrolysis of structured triglyceride,1,3-dioleoyl-2-palmitoylglycerol, suggested that both the enzymes hydrolyse the fatty acids at both the positions. The observed discrimination against ω-3 fatty acids by PLA1 appears to be due to its fatty acid selectivity rather than positional specificity. These studies suggest that PLA1 could be used as a potential enzyme for selective concentrationof ω-3 fatty acids.

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Enrichment of omega-3 fatty acids (ω-3 FAs) in natural oils is important to realize their health benefits. Lipases are promising catalysts to perform this enrichment, however, fatty acid specificity of lipases is poor. We attempted to improve the fatty acid selectivity of a lipase from Geobacillus thermoleovorans (GTL) by two approaches. In a semi-rational approach, amino acid positions critical for binding were identified by docking the substrate to the GTL and best substitutes at these positions were identified by site saturation mutagenesis followed by screening to obtain a variant of GTL (CM-GTL). In the second approach based on rational design, a variant of GTL was designed (DM-GTL) wherein the active site was narrowed by incorporating two heavier amino acids in the lining of acyl-binding pocket to hinder access to bulky ω-3 FAs. The affinities DM-GTL with designed substrates were evaluated in silico. Both, CM-GTL and DM-GTL have shown excellent ability to discriminate against the ω-3 FAs during hydrolysis of oils. Engineering the binding pocket of an enzyme of a complex substrate, such as a triglyceride, by incorporating the information on substrate structure and computationally derived binding modes, has resulted in designing two efficient lipase variants with improved substrate selectivity.

We announce here the draft genome sequence of Brevibacillus laterosporus strain Lak 1210, isolated from mangrove soil. This alkaliphilic strain is an efficient chitin degrader and has the ability to control insects and inhibit phytopathogenic fungi. The assembly consists of 5,082,926 bp, with 4,321 protein-coding sequences and a GC content of 41.15%.

Peptides designed with residues that have high propensity to occur in β-turns, form β-hairpin structures in apolar solvents as well in polar organic solvents such as dimethyl sulfoxide (DMSO), methanol and varying percentages of DMSO in chloroform (CHCl3). Presumably due to limited solubility, their conformations have not been investigated by experimental methods in water. We have examined the conformations of such designed peptides that fold into well-defined β-hairpin structures facilitated by β-turns, in the crystalline state and in solution, by Molecular Dynamics Simulations (MDS). The peptides fold into β-hairpin structures in water, starting from extended conformation. In DMSO, folding into β-hairpin structures was not observed, starting from extended conformation. However, when the starting structure is in β-hairpin conformation, unfolding is not observed during MDS in DMSO. Water clearly favours folding of short, hydrophobic peptides into β-turn and β-hairpin conformations from extended structures. DMSO does not have a denaturing effect on short, hydrophobic peptides.