Effect of Gold Nanoparticles on the Conformation of Bovine Serum Albumin: Insights from CD Spectroscopic Analysis and Molecular Dynamics Simulations

Samal Kaumbekova; Naoya Sakaguchi; Dhawal Shah; Masakazu Umezawa

doi:10.1021/acsomega.4c06409

Effect of Gold Nanoparticles on the Conformation of Bovine Serum Albumin: Insights from CD Spectroscopic Analysis and Molecular Dynamics Simulations

ACS Omega. 2024 Dec 3;9(50):49283-49292. doi: 10.1021/acsomega.4c06409. eCollection 2024 Dec 17.

Authors

Samal Kaumbekova^{1

2}, Naoya Sakaguchi³, Dhawal Shah², Masakazu Umezawa^{1

3}

Affiliations

¹ Department of Medical and Robotic Engineering Design, Faculty of Advanced Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan.
² Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr 53, Astana 010000, Kazakhstan.
³ Department of Materials Science and Technology, Graduate School of Advanced Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan.

Abstract

With the development of nanotechnology, there is growing interest in using nanoparticles (NPs) for biomedical applications, such as diagnostics, drug delivery, imaging, and nanomedicine. The protein's structural stability plays a pivotal role in its functionality, and any alteration in this structure can have significant implications, including disease progression. Herein, we performed a combined experimental and computational study of the effect of gold NPs with a diameter of 5 nm (5 nm Au-NPs) on the structural stability of bovine serum albumin (BSA) protein in the absence and presence of NaCl salt. Circular dichroism spectroscopy showed a loss in the secondary structure of BSA due to the synergistic effect of Au-NPs and NaCl, and Thioflavin T fluorescence assays showed suppressed β-sheet formation in the presence of Au-NPs in PBS, emphasizing the intricate interplay between NPs and physiological conditions. Additionally, molecular dynamics (MD) simulations revealed that 5 nm Au-NP induced changes in the secondary structure of the BSA monomer in the presence of NaCl, highlighting the initial binding mechanism between BSA and Au-NP. Furthermore, MD simulations explored the effect of smaller Au-NP (3 nm) and nanocluster (Au-NC with the size of 1 nm) on the binding sites of the BSA monomer. Although the formation of stable BSA-Au conjugates was revealed in the presence of NPs of different sizes, no specific protein binding sites were observed. Moreover, due to its small size, 1 nm Au-NC decreased helical content and hydrogen bonds in the BSA monomer, promoting protein unfolding more significantly. In summary, this combined experimental and computational study provides comprehensive insights into the interactions among Au nanosized substances, BSA, and physiological conditions that are essential for developing tailored nanomaterials with enhanced biocompatibility and efficacy.