Circular Dichroism

Understanding the Effect of Secondary Structure on Molecular Interactions of Poly-l-lysine with Different Substrates by SFA

“…As shown in Figure , no considerable changes in peak position were observed, indicating that (1) the respective secondary structures were induced successfully through controlling solution conditions and (2) the different secondary structures of PLL persist upon adsorption on quartz and subsequent buffer change. Previous studies have reported that a 3 nm shift in CD spectra peak position does not imply an overall difference in secondary structure, , thus, the minor peak position shifts reported in Table does not imply an overall change in the secondary structure. The spectra deconvolution based on a method reported by Whitmore et al suggested that there would be at least 75% α-helix content in Figure a.…”

“…This PLL α-helix solution was then heated to 70 °C for 50 min in order to transform the α-helix PLL into a β-sheet conformation, which was retained upon cooling the solution to 37 °C. The change in PLL secondary structure was confirmed using CD, where α-helix structures exhibit a characteristic maximum peak at ∼190 nm and two minimum peaks at ∼205 and ∼222 nm, and β-sheet structures exhibit a characteristic maximum and minimum peak at ∼195 and ∼215 nm, respectively. , …”