Gemini Surfactants Affect the Structure, Stability, and Activity of Ribonuclease Sa

Abstract

Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA.

Effect of spacer chain length on the liquid structure of aqueous dicationic ionic liquid solutions: molecular dynamics studies

“…Gemini surfactants contain two polar head groups linked by a rigid or flexible spacer. Due to their low CMCs, slow millisecond monomer-micelle kinetics 7 and smaller aggregation number, they are extensively used in the field of biochemical research, [8][9][10] gene delivery, [11][12][13] drug delivery 14,15 and antimicrobial activity. [3][4][5][6] So, one can use a small amount of gemini surfactants instead of the large amount required for conventional surfactants to achieve the same results.…”

Comparative effect of cationic gemini surfactant and its monomeric counterpart on the conformational stability and activity of lysozyme

“…Some recent reports on new generation surface active agents called as "Gemini surfactant" also suggests their potential role in protein stability and activity. 16,17 Interaction of gemini surfactants with proteins suggest that they have stronger binding with proteins as compared to conventional surfactants. [18][19][20] This difference in binding is majorly governed due to dissimilarity in their physiochemical properties they possess due to the presence of two long hydrocarbon chains and two ionic groups attached covalently to a spacer group.…”

“…21 Recently we have reported the possible role of gemini surfactants in refolding of globular protein 23 and stability of membrane bound peptide. 24 Present communication is an attempt to get much deeper insight on the comparative effect of biscationic methyl ethanol amine gemini surfactant C 16 H 33 (CH 3 ) 2 C 2 H 4 OHN + -(CH 2 ) 6 -N + C 2 H 4 OH(CH 3 ) 2 C 16 H 33 2Br À abbreviated as G 16 with spacer length -(CH 2 ) 6 and its monomeric counterpart C 16 H 33 (CH 3 ) 2 C 2 H 4 OHN + Br À abbreviated as M 16 on the structural stability and antibacterial activity of hen egg white lysozyme (HEWL) using various spectroscopic techniques and molecular docking method. The structure of M 16 and G 16 has been depicted in Scheme 1.…”

“…The effect of gemini surfactant on lysozyme have also been reported previously, 19,32,33 however relatively less interaction studies have been made till now. The aim of the present study is to decipher the binding interaction of M 16 and G 16 on the conformational stability and antibacterial activity of HEWL. The interaction pattern of M 16 and G 16 with lysozyme before and aer cmc has been shown in Scheme 2.…”

“…The aim of the present study is to decipher the binding interaction of M 16 and G 16 on the conformational stability and antibacterial activity of HEWL. The interaction pattern of M 16 and G 16 with lysozyme before and aer cmc has been shown in Scheme 2. We hope that this study will endow greater landscape on the difference in binding of respective surfactants specically with HEWL which will prove to be helpful from medicinal and pharmaceutical point of view.…”