Deciphering the binding behaviours of BSA using ionic AIE-active fluorescent probes.

Area of Science:

• Biochemistry
• Biophysics
• Fluorescence Spectroscopy

Background:

• Bovine serum albumin (BSA) is a crucial transport protein with complex folding dynamics.
• Understanding protein conformational changes is vital for drug delivery and disease research.
• Exogenous fluorescent probes offer sensitive methods for monitoring protein structure.

Purpose of the Study:

• To investigate the binding behaviors of BSA in native, unfolding, and refolding states.
• To utilize AIE-active fluorescent probes (M2 and M3) to monitor BSA conformational changes.
• To elucidate the role of electrostatic interactions in BSA folding and unfolding.

Main Methods:

• Monitoring emission changes of anionic (M2) and cationic (M3) AIE-active fluorescent probes.
• Utilizing BSA + M2 and BSA + M3 systems to signal conformational changes.
• Inducing denaturation through thermal and chemical stimuli.

Main Results:

• Both M2 and M3 probes showed enhanced emission upon binding to BSA's hydrophobic cavity in subdomain IIA.
• The study confirmed a multi-step unfolding process for BSA, including a molten-globule intermediate.
• Anionic and cationic probe modifications highlighted the role of electrostatic interactions in BSA folding/unfolding.

Conclusions:

• BSA undergoes a multi-step unfolding process involving subdomain IIA rearrangement and molten-globule intermediate formation.
• Electrostatic interactions significantly influence the folding and unfolding pathways of BSA.
• AIE-active probes are effective tools for studying protein conformational dynamics and interactions.