Understanding structure-stability relationships of Candida antartica lipase B in ionic liquids

Two different water-immiscible ionic liquids (ILs), 1-ethyl-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, were used for butyl butyrate synthesis from vinyl butyrate catalyzed by Candida antarctica lipase B (CALB) at 2% (v/v) water...

Full description

Saved in:
Bibliographic Details
Published in:Biomacromolecules 2005-05, Vol.6 (3), p.1457-1464
Main Authors: DE DIEGO, Teresa, LOZANO, Pedro, GMOUH, Said, VAULTIER, Michel, IBORRA, José L
Format: Article
Language:English
Subjects:
Amino Acid Sequence - genetics
Bioconversions. Hemisynthesis
Biological and medical sciences
Biotechnology
Candida
Candida antarctica
Enzyme Stability - genetics
Fundamental and applied biological sciences. Psychology
Fungal Proteins
Lipase - chemistry
Lipase - genetics
Methods. Procedures. Technologies
Molecular Sequence Data
Osmolar Concentration
Protein Structure, Secondary - genetics
Solutions - chemistry
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Two different water-immiscible ionic liquids (ILs), 1-ethyl-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, were used for butyl butyrate synthesis from vinyl butyrate catalyzed by Candida antarctica lipase B (CALB) at 2% (v/v) water content and 50 degrees C. Both the synthetic activity and stability of the enzyme in these ILs were enhanced as compared to those in hexane. Circular dichroism and intrinsic fluorescence spectroscopic techniques have been used over a period of 4 days to determine structural changes in the enzyme associated with differences in its stability for each assayed medium. CALB showed a loss in residual activity higher than 75% after 4 days of incubation in both water and hexane media at 50 degrees C, being related to great changes in both alpha-helix and beta-strand secondary structures. The stabilization of CALB, which was observed in the two ILs studied, was associated with both the maintenance of the 50% of initial alpha-helix content and the enhancement of beta-strands. Furthermore, intrinsic fluorescence studies clearly showed how a classical enzyme unfolding was occurring with time in both water and hexane media. However, the structural changes associated with the incubation of the enzyme in both ILs might be attributed to a compact and active enzyme conformation, resulting in an enhancement of the stability in these nonaqueous environments.
ISSN:1525-7797
1526-4602
DOI:10.1021/bm049259q