Sugar is the key to the nicotine rush according to new research

The debate over how signals pass from the outside of a cell to the inside is a long-standing one.

Some researchers had suggested that when a chemical such as nicotine binds to an ion channel protein on the cell surface, the protein starts a “conformational wave” that propagates a signal through the protein body to the cell membrane, Chen said.

But the molecular basis of such a wave in nAChR or any other protein has not been clearly established.

Instead, the Chen and Wang groups’ study of crystal structure suggested a simple mechanical role for sugar molecules attached to the surface of the receptor.

“They serve as the link between the neurotransmitter binding site and the membrane region where the gate is located,” Chen said.

“The sugar is kind of like a hinge. It’s pulling the door open and closed.”

Cutting the sugar chains stopped the gate’s operation: “The sugar is critical, in my opinion”, said Chen.

The researchers also found a water molecule deep in the receptor’s core – significant because proteins normally are filled with hydrophobic (water repellent) matter that helps the structure hold its shape according to Chen.

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