CONFORMATIONAL-ANALYSIS OF LYS(11-36), A PEPTIDE DERIVED FROM THE BETA-SHEET REGION OF T4 LYSOZYME, IN TFE AND SDS

The solution conformation of a peptide LYS(11-36), which corresponds t o the beta-sheet region in T4 lysozyme, has been examined in aqueous s olution, TFE, and SDS micelles by CD and H-1 NMR spectroscopy. Seconda ry structure predictions suggest some beta-sheet and turn character in aqueous solution but predict a helical conformation in a more hydroph obic environment. The predictions were supported by the CD and NMR stu dies which showed the peptide to be relatively unstructured in aqueous solution, although there was some evidence of a beta-turn conformer w hich was maintained in 200 mM SDS and, to a lesser extent, in 50% TFE. The peptide was significantly helical in the presence of either 50% T FE or 200 mM SDS. TFE and SDS titrations showed that the peptide could form helical, sheet, or extended structure depending on the TFE or SD S concentration. The studies indicate that peptide environment is the determining factor in secondary structure adopted by LYS(11-36).