Gupta P, Verma R, Verma AK, Chattopadhyay PC. A versatile tool in controlling aggregation and Ag nanoparticles assisted in vitro folding of thermally denatured zDHFR.
Biochem Biophys Rep 2020;
24:100856. [PMID:
33294634 PMCID:
PMC7695922 DOI:
10.1016/j.bbrep.2020.100856]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 11/19/2022] Open
Abstract
Background
Proteins have tendency to form inactive aggregates at higher temperatures due to thermal instability. Maintenance of thermal stability is essential to gain the protein in sufficient quantity and biologically active form during their commercial production.
Methods
BL21-DE3 Rosetta E. coli cells which contains plasmid pET43.1a vector was used for producing zDHFR protein commercially. The purification of N-terminal Histidine tagged zDHFR was performed by Immobilized Metal Ion chromatography (IMAC). Investigations were performed in existence and non existence of Silver nanoparticles (AgNPs). The inactivation kinetics of zDHFR in existence and non existence of AgNPs were monitored over a range of 40–80 °C as monitored by UV–Visible absorption spectroscopy.
Results
The protein completely lost its activity at 55 °C. Kinetics of inactivated zDHFR follows first order model in presence and absence of AgNPs. Decrease in rate constant (k) values at respective temperatures depicts that AgNPs contribute in the thermostability of the protein. AgNPs also assists in regaining the activity of zDHFR protein.
Conclusions
AgNPs helps in maintaining thermostability and reducing the aggregation propensity of zDHFR protein.
General significance
Result explains that AgNPs are recommended as a valuable system in enhancing the industrial production of biologically active zDHFR protein which is an important component in folate cycle and essential for survival of cells and prevents the protein from being aggregated.
Recombinant proteins have the ability to get aggregated during their commercial production due to factors like temperature, pH, etc. Aggregation of protein can be prevented with the help of AgNPs by increasing their thermal stability.
AgNPs maintain the stability of thermally-denatured zDHFR under high temperatures which is confirmed by kinetic and thermodynamic parameters.
AgNPs also assists in refolding of the thermally-denatured protein which proves that AgNPs plays a supportive role in maintaining the stability of the protein and thus preventing it from being aggregated.
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