PH Dependence of the Coiled-Coil Structure of Keratin Intermediate Filament in Human Hair by 13C NMR Spectroscopy and the Mechanism of Its Disruption
February 1998
in “
Polymer journal
”
TLDR Keratin structure in hair is stable at pH 5-6 but disrupts between pH 6-7.
The study used 13C NMR spectroscopy to investigate the pH dependence of the coiled-coil structure of keratin intermediate filament (KIF) in human hair. It was found that the coiled-coil structure remained stable at pH 5.0 and 6.0 but was disrupted between pH 6.0 and 7.0, leading to a random coil structure. This disruption was marked by increased peak intensities of side chains from charged amino acids (Glu, Asp, Lys, Arg) and hydrophobic amino acids (Leu, Ile), indicating weakened ion-pairing and hydrophobic interactions. The coiled-coil structure could be restored by readjusting the pH back to 6.0, suggesting that both types of interactions are crucial for its stability.
