Engineering Cytochrome C with Quantum Dots and Ionic Liquids: A Win-Win Strategy for Protein Packaging against Multiple Stresses

Abstract

Enhancing the structural stability and catalytic activity of Cytochorme c (Cyt C) against harsh process conditions would boost its use in biocatalysis. Herein, a new protein engineering strategy with improved efficacy is demonstrated through judicious task-specific functionalization of Cyt C with quantum dots (QDs) and ionic liquids (ILs). Mn 2+ doped ZnS QD and ILs ([Cho][Ac]; [Cho][Dhp]) were concomitantly used to decorate Cyt C, which was characterized using various analytical tools. The peroxidase activity at room temperature of engineered Cyt C (Cyt C-QD-IL) increased markedly (1.2 to 3.5-fold) as compared to that for bare Cyt C, Cyt C with QD, and Cyt C with ILs. Further, Cyt C-QD-IL showed better catalytic activity under various stresses such as high temperature (110 °C), presence of a chemical denaturant (6 M GuHCl), high oxidative stress (30 min H 2 O 2 ), and presence of proteases. Molecular docking results indicate that QD interacted with the active site of Cyt C and IL interacted with side chain amino acids via electrostatic and H-bonding interactions. Such favorable allosteric interactions might be behind the improved activity of Cyt C-QD-IL. The observed catalytic activity is in harmony with the structural stability of the protein as confirmed by UV−vis, ATR-IR, and CD analysis. Thus, the unveiled strategy represents an innovative dimension of protein packaging foreseeing the development of more robust biocatalysts that can be used at high temperatures.

Unprecedented enhancement and preservation of the peroxidase activity of cytochrome-c packaged with ionic liquid-modified gold nanoparticles by offsetting temperature and time stresses

“…In the field of fuel energy, the stabilization of poly(methyl methacrylate) (PMMA)-grafted magnetic NPs has been improved in ILs with polystyrene sulfonate (PSS). 30 Moreover, Shet et al 31 has verified the accountability of Cyt- c , engineered with Mn 2+ -doped ZnS quantum dots (QDs) and cholinium ionic liquids. The combined effect of engineered Cyt- c has more catalytic activity in compared to that of Cyt- c separately in the presence of QD and ILs under stress of high temperature and chemical denaturants.…”

Enhancement of Peroxidase Activity in Magnetic Ionic Liquids

“…34 Recently, Mondal and coworkers observed enhancement in the peroxidase activity of Cyt-c in the presence of Mn-doped quantum dots and choline-based ILs. 35 However, to the best of our knowledge, there are no reports on the effect of MILs on the activity of Cyt-c. Herein, we have attempted to study the effect of MILs on the peroxidase activity of Cyt-c. In this context, iron and manganese are known to be both magnetically and biologically active.…”

Nano-structured Hydrotrope-Caged Cytochrome c with Boosted Stability in Harsh Environments: A Molecular Insight

“…24 The protein is highly vulnerable to denaturation under prevailing stress conditions such as extreme temperatures, oxidative stress, and proteolytic and chemical denaturants. 25 Recently, a surface modification strategy using quantum dots, metal-organic frameworks, 26 , and DNA was reported to enhance the stability of Cyt c. 25,27 However, the stability of the protein when confined within a hydrotrope system has not yet been reported. Considering the hydrotropism and probability of nano-structuring, 24 the present study aimed to cage Cyt c in ATP and [Cho][Sal] IL-based hydrotropes, and thereby improve the activity and stability of the protein in gentle and harsh environments (such as high temperature, chemical denaturants, protease digestion, and oxidative stress).…”