Ionic liquid activated Bacillus subtilis lipase A variants through cooperative surface substitutions. Issue 10 (22nd July 2015)

• Record Type: Journal Article
• Authors: Zhao, Jing; Jia, Ning; Jaeger, Karl‐Erich; Bocola, Marco; Schwaneberg, Ulrich
• Is Part Of: Biotechnology and bioengineering. Volume 112:Issue 10(2015:Oct.)
• Page Start: 1997
• Page End: 2004
• Publication Date: 2015-07-22
• Subjects: Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25617
• Languages: English
• ISSNs: 0006-3592

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>ABSTRACT</title> <sec id="bit25617-sec-0001" sec-type="section"> <p>The interest in performing enzyme‐catalyzed reactions in amphiphilic systems, e.g., imidazolium‐based ionic liquids (ILs) or surfactants, has been increased over the past decades. Directed protein evolution has been successful in tailoring enzymes for desired properties. Herein, nine IL‐resistant <italic>Bacillus subtilis</italic> lipase A variants, particularly an IL‐activated variant M1 (M134N/N138S/L140S), were identified by directed evolution. For instance, variant M2 (M134R/L140S) showed almost doubled specific activity (16.9 vs. 9.4 U/mg) and resistance (233% vs. 111%) at 9 vol% 1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate ([C<sub>4</sub>mim][TfO]) compared with wild–type. The specific activities and resistance of purified individual single and double variants have been studied in five different IL‐aqueous mixtures. The re‐activation of lipase variant M1 (not wild–type) at high IL concentration was attributed to the cooperative effect of three surface substitutions (M134N, N138S, L140S) near the substrate‐binding cleft. The presence of IL/substrate clusters under assay conditions was likely related to the re‐activation effect. This study provides first example of IL‐activated lipase variant generated by protein engineering, and helps to better understand the protein‐IL interaction. Biotechnol. Bioeng. 2015;112: 1997–2004. © 2015 Wiley Periodicals, Inc.</p> </sec> </abstract>