Date of Award
Dr. Maria Ngu
Dr. Joyce W. O'Rourke
Dr. Beverly Wade
Reports on peptides that are rich in D-alanine indicate that peptides with this structural motif adopt a specific secondary structure. In this study, two cyclic tetrapeptides cyclo[Leu-D-Ala], where Xaa is Glu or Lys, was studied by circular dichroism (CD). The conformational stability of these peptides was investigated by varying the temperature, solvent, pH, and concentration of the peptide solutions. When these conditions were varied, the CD measurements in each condition did not produce any significant changes. The CD of both peptides exhibits two positive CD bands at 211 nm and 222 nm and a third positive CD band below 190 nm and two negative CD bands at 200 nm and 238 nm. The general CD profile corresponds to a P-turn structure. When the conditions were varied, the CD measurements under each condition did not produce any significant changes. The results of the study indicate that cyclic tetrapeptides containing D-Ala do adopt a P-turn structure that is conformationally stable.
Bowie, Toni, "Conformational analysis of small peptides by circular dichroism" (2002). Electronic Dissertation and Theses. 28.