Open AccessMutations towards enantioselectivity adversely affect secretion of Pseudomonas aeruginosa lipase
Author(s) -
Hausmann Sascha,
Wilhelm Susanne,
Jaeger KarlErich,
Rosenau Frank
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01107.x
Subject(s) - lipase , enantiopure drug , secretion , hydrolysis , enantioselective synthesis , biochemistry , enzyme , pseudomonas aeruginosa , amino acid , chemistry , pseudomonas , directed evolution , triacylglycerol lipase , biology , bacteria , gene , mutant , catalysis , genetics
Lipases are important biocatalysts used as detergent additives to manufacture biodiesel, and in particular, for the production of enantiopure compounds such as alcohols, amines and carboxylic acids. Extensive efforts were conducted trying to optimize lipase properties and lipase LipA of Pseudomonas aeruginosa comprises the best‐studied example in terms of optimizing enantioselectivity by application of numerous directed evolution methods. Its enantioselectivity in the asymmetric hydrolysis of the model substrate 2‐methyldecanoic acid p ‐nitrophenyl ester was increased from E =1.1 for the wild‐type enzyme to E =51 for the best (S)‐enantioselective variant which carried six amino acid exchanges. We have observed that overexpression of this variant in the homologous host resulted in only marginal yields of enzyme in the bacterial culture supernatant, suggesting that the enantioselective LipA variant was secreted with only low efficiency. Hence, we have analysed the secretion of this lipase variant and compared it to variants carrying either the respective single mutations or some combinations. We report here the identification of two amino acid substitutions located on the protein surface, which significantly impair lipase secretion.