Vibrational Coupling between Helices Influences the Amide I Infrared Absorption of Proteins: Application to Bacteriorhodopsin and Rhodopsin

What is it about?

Calculations of the protein infrared absorption of helix bundles revealed that the spectrum is influenced by coupling of C=O (amide I) vibrations in different helices. This shows that the amide I band is influenced not only by secondary structure but also by tertiary structure.

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Why is it important?

This work provides a long sought explaination for the unusually high amid I frequency of bacteriorhodopsin trimers.