TY - JOUR
T1 - Enhanced structural stability of insulin aspart in cholinium aminoate ionic liquids
AU - Sundaram, Vidya
AU - Ramanan, Ramakrishnan Nagasundara
AU - Selvaraj, Manikandan
AU - Vijayaraghavan, R.
AU - MacFarlane, Douglas R.
AU - Ooi, Chien Wei
N1 - Funding Information:
The authors acknowledge the Fundamental Research Grant Scheme (FRGS) [ FRGS/1/2018/STG04/MUSM/02/1 ] by the Ministry of Higher Education, Malaysia (MOHE). Douglas R. MacFarlane is grateful for support of this work by the Australian Research Council through his Australian Laureate Fellowship (FL120100019).
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/5/31
Y1 - 2022/5/31
N2 - Cholinium aminoates [Ch][AA] have gained tremendous interest as a promising ionic liquid medium for the synthesis and storage of proteins. However, high alkalinity of [Ch][AA] limits its usage with pH-sensitive proteins. Here, we probed the structure, stability, and interactions of a highly unstable therapeutic protein, insulin aspart (IA), in a range of buffered [Ch][AA] (b-[Ch][AA]) using a combination of biophysical tools and in silico pipeline including ultraviolet-visible, fluorescence, and circular dichroism spectroscopies, dynamic light scattering measurements and molecular docking. b-[Ch][AA] used in the study differed in concentrations and their anionic counterparts. We reveal information on ion and residue specific solvent–protein interactions, demonstrating that the structural stability of IA was enhanced by a buffered cholinium prolinate. In comparison to the glycinate and alaninate anions, the hydrophilic prolinate anions established more hydrogen bonds with the residues of IA and provided a less polar environment that favours the preservation of IA in its active monomeric form, opening new opportunities for utilizing [Ch][AA] as storage medium.
AB - Cholinium aminoates [Ch][AA] have gained tremendous interest as a promising ionic liquid medium for the synthesis and storage of proteins. However, high alkalinity of [Ch][AA] limits its usage with pH-sensitive proteins. Here, we probed the structure, stability, and interactions of a highly unstable therapeutic protein, insulin aspart (IA), in a range of buffered [Ch][AA] (b-[Ch][AA]) using a combination of biophysical tools and in silico pipeline including ultraviolet-visible, fluorescence, and circular dichroism spectroscopies, dynamic light scattering measurements and molecular docking. b-[Ch][AA] used in the study differed in concentrations and their anionic counterparts. We reveal information on ion and residue specific solvent–protein interactions, demonstrating that the structural stability of IA was enhanced by a buffered cholinium prolinate. In comparison to the glycinate and alaninate anions, the hydrophilic prolinate anions established more hydrogen bonds with the residues of IA and provided a less polar environment that favours the preservation of IA in its active monomeric form, opening new opportunities for utilizing [Ch][AA] as storage medium.
KW - Cholinium aminoates
KW - Insulin aspart
KW - Ionic liquids
KW - Protein stabilization
KW - Protein-IL interaction
UR - http://www.scopus.com/inward/record.url?scp=85127162149&partnerID=8YFLogxK
U2 - 10.1016/j.ijbiomac.2022.03.100
DO - 10.1016/j.ijbiomac.2022.03.100
M3 - Article
C2 - 35331796
AN - SCOPUS:85127162149
SN - 0141-8130
VL - 208
SP - 544
EP - 552
JO - International Journal of Biological Macromolecules
JF - International Journal of Biological Macromolecules
ER -