Molecular dynamics insights into pulsed electric field-induced structural and functional changes in polygalacturonase

Area of Science:

• Food science and technology
• Biophysics
• Biochemistry

Background:

• Pulsed electric field (PEF) is a non-thermal sterilization method for fruit juices.
• PEF affects enzymes like polygalacturonase (PG), which impacts juice turbidity.
• The molecular mechanisms of PEF's effect on PG are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms of pulsed electric field (PEF) effects on polygalacturonase (PG) structure and activity.
• To determine the threshold electric field strength for significant PG structural changes.
• To provide insights into enzyme control in fruit juice preservation using PEF.

Main Methods:

• Molecular dynamics simulations were employed to model PEF interactions with PG.
• Protein structural changes, hydrogen bonds, and active site positions were analyzed.
• Experimental assays measured PG activity under varying PEF strengths.

Main Results:

• PEF strengths below 1 V/nm caused minor, reversible structural changes in PG.
• PEF strengths above 1 V/nm led to irreversible loss of secondary structure and exposure of the hydrophobic core.
• PG activity significantly decreased with increasing PEF strength, correlating with structural damage.

Conclusions:

• PEF at high electric field strengths (>1 V/nm) induces irreversible structural damage to PG.
• This structural disruption leads to a loss of enzyme activity, offering a method for enzyme control in fruit juices.
• PEF shows potential as a tool for managing enzyme activity in fruit juice preservation.