How do membrane lipids contribute to the structure and function of protein pores? A new study from the National Institute of Chemistry in Slovenia offers detailed insights using cryo-electron microscopy (cryo-EM), molecular dynamics simulations, and electrophysiology.

The researchers investigated Fav, a pore-forming toxin from the coral Orbicella faveolata. In this study, it revealed unexpected structural roles for cholesterol and sphingomyelin in pore formation and stabilization. The team used high-resolution cryo-EM to examine how the pores are built and how they interact with surrounding lipids.

To study how the pore behaves in a membrane, the researchers used the Nanion Orbit mini platform, allowing them to record ion currents and monitor pore activity.

Key findings from the study:

• Each Fav pore is made up of 8 protein units and is stably associated with more than 100 lipid molecules.

• The protein is not simply placed in the membrane. It is tightly connected to surrounding lipids through hydrogen bonds, hydrophobic interactions, and cation-π interactions.

• Sphingomyelin (SM) plays a key role in helping Fav proteins oligomerize, meaning it supports the assembly of the pore.

• In cholesterol-containing membranes, the researchers observed clusters of four cholesterol molecules located below each protein unit. These cholesterol clusters help stabilize the pore and reduce current noise during electrophysiological recordings.

• Some lipids are located between protein units and act like structural glue. Others are involved in bridging interactions between lipids, providing additional stability to the pore.

This study shows that lipids are not just passive components of the membrane. They actively influence how protein structures assemble and function. It also helps explain how specific lipids like cholesterol and sphingomyelin support pore stability and activity.

These insights may contribute to future work in areas such as nanopore sensing, where protein pores are used to detect molecules like DNA or proteins.

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Read the full paper here: Cryo-EM structures of a protein pore reveal a cluster of cholesterol molecules and diverse roles of membrane lipids

Learn more about our Orbit mini platform: Orbit mini – Nanion Technologies