Conductance Changes in Bovine Serum Albumin Caused by Drug-Binding Triggered Structural Transitions.

Jing Yu,Xiaoyue Zhang,Yun Chen,Yue Zheng,Liqun Xiong

doi:10.3390/ma12071022

Abstract

Proteins, due to their binding selectivity, are promising candidates for fabricating nanoscale bio-sensors. However, the influence of structural change on protein conductance caused by specific protein-ligand interactions and disease-induced degeneration still remains unknown. Here, we excavated the relationship between circular dichroism (CD) spectroscopy and conductive atomic force microscopy (CAFM) to reveal the effect of the protein secondary structures changes on conductance. The secondary structure of bovine serum albumin (BSA) was altered by the binding of drugs, like amoxicillin (Amox), cephalexin (Cefa), and azithromycin (Azit). The CD spectroscopy shows that the α-helical and β-sheet content of BSA, which varied according to the molar ratio between the drug and BSA, changed by up to 6%. The conductance of BSA monolayers in varying drug concentrations was further characterized via CAFM. We found that BSA conductance has a monotonic relation with α-helical content. Moreover, BSA conductance seems to be in connection with the binding ability of drugs and proteins. This work elucidates that protein conductance variations caused by secondary structure transitions are triggered by drug-binding and indicate that electrical methods are of potential application in protein secondary structure analysis.

Highlights

The way of using single organic molecules or molecular monolayers as electronic components has attracted extensive interest because it is considered as a possible solution to the physical limitations of nano-scale electronic development [1]
We comprehensively investigated the conductance of variation in drug-carrying proteins elicited by secondary structure transitions due to drug-binding
The secondary structure of bovine serum albumin (BSA) was altered upon binding with the drugs amoxicillin, cephalexin, and azithromycin

Summary

Introduction

The way of using single organic molecules or molecular monolayers as electronic components has attracted extensive interest because it is considered as a possible solution to the physical limitations of nano-scale electronic development [1]. Proteins are promising candidate to be selected as electronic components due to their binding selectivity [2] and their endurance of chemo-mechanical, electro-mechanical, opto-mechanical, and opto-electronic processes. Proteins have been studied in order to realize implantable bio-sensors for monitoring chemicals and diagnostics [3,4,5,6]. The change rules allow the development of drug monitoring, environmental toxin detection, and early disease detection with high sensitivities and low detection limits [7,8,9]. Compared to other techniques, such as the spectroscopic approach, the electrical method asks for much simpler instruments, it has the advantage of a high portability, low-cost, and rapidness

Methods

Discussion

Conclusion