What is the secondary structural change of poly-L-lysine when TFE is added?

What is the secondary structural change of poly-L-lysine when TFE is added?

• A. Random coil to α-helix
• B. α-helix to random coil
• C. β-sheet to random coil
• D. α-helix to β-sheet

Answer: (D)

When tetrafluoroethanol (TFE) is added to poly-L-lysine, a well-known phenomenon in protein chemistry occurs that influences the secondary structure of the polypeptide. Poly-L-lysine, which can adopt an α-helical structure, tends to be stabilized by the presence of TFE. However, TFE also has the ability to promote the formation of β-sheets, especially over time or with higher concentrations. As a result, the addition of TFE can lead to a conversion from an α-helix to a β-sheet structure. This is attributed to the increase in the stability of the intramolecular hydrogen bonding that characterizes β-sheets, which TFE can facilitate. Therefore, the secondary structural change of poly-L-lysine upon the addition of TFE is from an α-helix to a β-sheet configuration. This transformation highlights the impact of solvent environments on the conformational properties of polypeptides and proteins.

When tetrafluoroethanol (TFE) is added to poly-L-lysine, a well-known phenomenon in protein chemistry occurs that influences the secondary structure of the polypeptide. Poly-L-lysine, which can adopt an α-helical structure, tends to be stabilized by the presence of TFE. However, TFE also has the ability to promote the formation of β-sheets, especially over time or with higher concentrations.

As a result, the addition of TFE can lead to a conversion from an α-helix to a β-sheet structure. This is attributed to the increase in the stability of the intramolecular hydrogen bonding that characterizes β-sheets, which TFE can facilitate. Therefore, the secondary structural change of poly-L-lysine upon the addition of TFE is from an α-helix to a β-sheet configuration. This transformation highlights the impact of solvent environments on the conformational properties of polypeptides and proteins.