H-1-NMR SPECTROSCOPY REVEALS THAT MOUSE HSP25 HAS A FLEXIBLE C-TERMINAL EXTENSION OF 18 AMINO-ACIDS

The small heat-shock proteins (Hsps) exist as large and stabilising non-native proteins in a chaperone-like manner. Two-dimensional H-1 NMR spectroscopy of mouse Hsp25 reveals that the last 18 amino acids have great flexibility with motion that is essentially independent of the domain care of the protein. The lens protein, alpha-crystallin, is homologous to Hsp25 and its two subunits also have flexible C-terminal extensions. The flexible region in Hsp25 encompasses exactly that expected from sequence comparison with alpha-crystallin implying that both proteins have similar structures and that the C-terminal extensions could be of functional importance for both proteins.