ORGN 909 |
| Highly fluorinated amino acids have been used to stabilize helical proteins, with limited studies on sheet-containing proteins. Herein, we present the effect of these highly fluorinated amino acids on two protein secondary structures: alpha-helix and beta-sheet. The helix propensity was measured using Ala-based peptides, whereas the beta-sheet propensity was measured using protein G B1 domain (GB1). Various amino acids were studied including 5,5,5,5',5',5'-hexafluroleucine, 5,5,5',5'-tetrafluoroleucine, pentafluorophenylalanine, leucine, phenylalanine, and alanine. The peptides and proteins were synthesized by solid phase peptide synthesis. The circular dichroism spectra of the Ala-based peptides were used to calculate the helix propensity. Thermal denaturation of GB1 derivatives were monitored by circular dichroism spectroscopy and used to obtain the sheet propensity. Helix propensity decreased significantly upon fluorination. In contrast, sheet propensity increased upon introducing the fluorines. Therefore, highly fluorinated amino acids may be more suitable for stabilizing beta-sheets in sheet-containing proteins compared to helical proteins. |
|
Proteins, Peptides, Amino Acids, and Enzyme Inhibitors
8:00 AM-12:00 PM, Thursday, August 23, 2007 BCEC -- 258B, Oral
Division of Organic Chemistry |