Gold Nanoparticles Augment N-Terminal Cleavage and Splicing Reactions in Mycobacterium tuberculosis SufB

Ananya Nanda; Sourya Subhra Nasker; Anoop K Kushwaha; Deepak Kumar Ojha; Albert K Dearden; Saroj K Nayak; Sasmita Nayak

doi:10.3389/fbioe.2021.773303

Gold Nanoparticles Augment N-Terminal Cleavage and Splicing Reactions in Mycobacterium tuberculosis SufB

Front Bioeng Biotechnol. 2021 Dec 23:9:773303. doi: 10.3389/fbioe.2021.773303. eCollection 2021.

Authors

Ananya Nanda¹, Sourya Subhra Nasker¹, Anoop K Kushwaha², Deepak Kumar Ojha¹, Albert K Dearden³, Saroj K Nayak², Sasmita Nayak¹

Affiliations

¹ School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India.
² School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, India.
³ Departments of Physics and Astronomy, College of Arts and Sciences, University of South Carolina, Columbia, SC, United States.

Abstract

Protein splicing is a self-catalyzed event where the intervening sequence intein cleaves off, joining the flanking exteins together to generate a functional protein. Attempts have been made to regulate the splicing rate through variations in temperature, pH, and metals. Although metal-regulated protein splicing has been more captivating to researchers, metals were shown to only inhibit splicing reactions that confine their application. This is the first study to show the effect of nanoparticles (NPs) on protein splicing. We found that gold nanoparticles (AuNPs) of various sizes can increase the splicing efficiency by more than 50% and the N-terminal cleavage efficiency by more than 45% in Mycobacterium tuberculosis SufB precursor protein. This study provides an effective strategy for engineering splicing-enhanced intein platforms. UV-vis absorption spectroscopy, isothermal titration calorimetry (ITC), and transmission electron microscopy (TEM) confirmed AuNP interaction with the native protein. Quantum mechanics/molecular mechanics (QM/MM) analysis suggested a significant reduction in the energy barrier at the N-terminal cleavage site in the presence of gold atom, strengthening our experimental evidence on heightened the N-terminal cleavage reaction. The encouraging observation of enhanced N-terminal cleavage and splicing reaction can have potential implementations from developing a rapid drug delivery system to designing a contemporary protein purification system.

Keywords: Mycobacterium tuberculosis; NP–intein corona; SufB; gold nanoparticles; splicing enhancement; splicing regulation.