2014•South African Journal of ChemistryOpen access
Conformational Comparison of Cyclic α3β Tetrapeptide vs. α3β Pentapeptide
Sachin A. Pawar, Amit M. Jabgunde, Glenn E. M. Maguire, Dilip D. Dhavale, Thavendran Govender, Hendrik G. Kruger, Fernando Alberício
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Abstract
The a-turn inducing sugar â-amino acid plays an important role in the formation of well-defined secondary structures of cyclic tetraand pentapeptide. Two tetraand one novel pentapeptide were synthesized from a sugar â-amino acid and the conformations of the compounds were established by NMR spectroscopy (EASY-ROESY) and compared with CD spectroscopic data. Although the a-turn conformation was dominant for both tetraand pentapeptide according to NMR spectroscopic analysis in DMSO, the pentapeptide exhibited the presence of a second conformation. CD spectroscopic results in methanol showed that the tetrapeptides have a a-turn conformation, while the pentapeptide has a random structure.