Amphipol trapping of a functional CYP system

Area of Science:

• Biochemistry
• Plant Molecular Biology
• Membrane Protein Biochemistry

Background:

• Cytochrome P450 (CYP) enzymes in plants are crucial for synthesizing bioactive natural products.
• These enzymes may form dynamic metabolons to enhance efficiency and prevent unwanted reactions.
• Studying membrane-bound CYPs in a functional state is challenging.

Purpose of the Study:

• To investigate the use of amphipols (APols) for solubilizing plant CYPs in a detergent-free system.
• To assess the impact of APols on the activity and interactions of specific CYPs involved in dhurrin biosynthesis.
• To evaluate APols as a tool for functional and structural studies of membrane-bound enzymes.

Main Methods:

• Solubilization of plant CYPs (CYP79A1, CYP71E1) and their electron partner (cytochrome P450 oxidoreductase, POR) using amphipol A8-35.
• Enzyme activity assays to determine the functional state of trapped CYPs and POR.
• Investigating enzyme interactions by substituting POR with an alternative electron donor system (NADPH-ferredoxin oxidoreductase and ferredoxin).

Main Results:

• An optimal protein-to-APol ratio (1:2 w/w) was determined for trapping CYP79A1, CYP71E1, and POR.
• Trapped CYP79A1 and POR retained individual enzymatic activity.
• Direct interaction between CYP79A1 and POR was hindered by APol, likely due to electrostatic repulsion.
• CYPs demonstrated catalytic activity when using an alternative electron donor system.

Conclusions:

• Amphipols provide a viable detergent-free method for solubilizing and studying plant CYPs.
• APols enable functional analysis of membrane-bound enzymes, although they may affect protein-protein interactions.
• This approach holds promise for future functional and structural investigations of membrane proteins.