title: Role of spacer length in interaction between novel gemini imidazolium surfactants and Rhizopus oryzae lipase.
abstract: An insight into the effects of new ionic liquid-type gemini imidazolium cationic surfactants on the structure and function of the lipases is of prime importance for their potential application. Changes in the activity, stability and structure of Rhizopus oryzae lipase in the presence of novel gemini surfactants, [C16-3-C16im]Br2 and [C16-12-C16im]Br2 were probed in the present study. Surfactant with shorter spacer length, [C16-3-C16im]Br2 was found to be better in improving the hydrolytic activity and thermal stability of the lipase. For both the surfactants, activation was concentration dependent. CD spectroscopy results showed a decrease in α-helix and an increase in β-sheet content in the presence of these surfactants. A higher structural change observed in presence of [C16-12-C16im]Br2 correlated with lower enzyme activity. Isothermal titration calorimetric studies showed the binding to be spontaneous in nature based on sequential two site binding model. The forces involved in binding were found to differ for the two surfactants proving that the spacer length is an important factor which governs the interaction. These surfactants could be used as promising components both in enzyme modification and media engineering for attaining the desired goals in biocatalytic reactions.
authors: Department of Agricultural & Food Engineering, Indian Institute of Technology, Kharagpur 721302, India.
authors: Sunita
authors: S
authors: Adak
authors: Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
authors: Sougata
authors: S
authors: Datta
authors: Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
authors: Santanu
authors: S
authors: Bhattacharya
authors: Department of Agricultural & Food Engineering, Indian Institute of Technology, Kharagpur 721302, India. Electronic address: rb@agfe.iitkgp.ernet.in.
authors: Rintu
authors: R
authors: Banerjee
mesh_terms: D002117:Calcitriol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D002384:Catalysis; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry*; D015394:Molecular Structure; D058767:Protein Unfolding; D012233:Rhizopus / Q000201:enzymology*; D013057:Spectrum Analysis; D013501:Surface-Active Agents / Q000737:chemistry* / Q000494:pharmacology; D013816:Thermodynamics
chemical_list: C411462:1,25-dihydroxy-21-(3-hydroxy-3-methylbutyl)vitamin D(3); D013501:Surface-Active Agents; D008049:Lipase; D002117:Calcitriol
keywords: Activity; Gemini imidazolium surfactant; Interactions; Lipase; Stability; Structural study