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Revealing the complexity of ionic liquid–protein interactions through a multi-technique investigation

DOI: 10.1038/s42004-020-0302-5 DOI Help

Authors: Liem Bui-Le (Imperial College London) , Coby J. Clarke (Imperial College London) , Andreas Brohl (Imperial College London) , Alex P. S. Brogan (University of Bristol) , James A. J. Arpino (Imperial College London) , Karen M. Polizzi (Imperial College London) , Jason P. Hallett (Imperial College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Communications Chemistry , VOL 3

State: Published (Approved)
Published: May 2020
Diamond Proposal Number(s): 19247 , 21035

Open Access Open Access

Abstract: Ionic liquids offer exciting possibilities for biocatalysis as solvent properties provide rare opportunities for customizable, energy-efficient bioprocessing. Unfortunately, proteins and enzymes are generally unstable in ionic liquids and several attempts have been made to explain why; however, a comprehensive understanding of the ionic liquid–protein interactions remains elusive. Here, we present an analytical framework (circular dichroism (CD), fluorescence, ultraviolet-visible (UV/Vis) and nuclear magnetic resonance (NMR) spectroscopies, and small-angle X-ray scattering (SAXS)) to probe the interactions, structure, and stability of a model protein (green fluorescent protein (GFP)) in a range (acetate, chloride, triflate) of pyrrolidinium and imidazolium salts. We demonstrate that measuring protein stability requires a similar holistic analytical framework, as opposed to single-technique assessments that provide misleading conclusions. We reveal information on site-specific ionic liquid–protein interactions, revealing that triflate (the least interacting anion) induces a contraction in the protein size that reduces the barrier to unfolding. Robust frameworks such as this are critical to advancing non-aqueous biocatalysis and avoiding pitfalls associated with single-technique investigations.

Journal Keywords: Chemical modification; Ionic liquids; Proteins

Subject Areas: Chemistry

Instruments: B21-High Throughput SAXS , B23-Circular Dichroism

Added On: 21/05/2020 13:08


Discipline Tags:

Catalysis Chemistry Chemical Engineering Engineering & Technology

Technical Tags:

Scattering Spectroscopy Small Angle X-ray Scattering (SAXS) Circular Dichroism (CD)