title: De novo design, synthesis and solution conformational study of two didehydroundecapeptides: effect of nature and number of amino acids interspersed between ΔPhe residues.
abstract: De novo design of peptides and proteins has recently surfaced as an approach for investigating protein structure and function. This approach vitally tests our knowledge of protein folding and function, while also laying the groundwork for the fabrication of proteins with properties not precedented in nature. The success relies heavily on the ability to design relatively short peptides that can espouse stable secondary structures. To this end, substitution with α,β-didehydroamino acids, especially α,β-didehydrophenylalanine (Δ(z)Phe), comes in use for spawning well-defined structural motifs. Introduction of ΔPhe induces β-bends in small and 3(10)-helices in longer peptide sequences. The present work aims to investigate the effect of nature and the number of amino acids interspersed between two ΔPhe residues in two model undecapeptides, Ac-Gly-Ala-ΔPhe-Ile-Val-ΔPhe-Ile-Val-ΔPhe-Ala-Gly-NH(2) (I) and Boc-Val-ΔPhe-Phe-Ala-Phe-ΔPhe-Phe-Leu-Ala-ΔPhe-Gly-OMe (II). Peptide I was synthesized using solid-phase chemistry and characterized using circular dichroism spectroscopy. Peptide II was synthesized using solution-phase chemistry and characterized using circular dichroism and nuclear magnetic resonance spectroscopy. Peptide I was designed to examine the effect of incorporating β-strand-favoring residues like valine and isoleucine as spacers between two ΔPhe residues on the final conformation of the resulting peptide. Circular dichroism studies on this peptide have shown the existence of a 3(10)-helical conformation. Peptide II possesses three amino acids as spacers between ΔPhe residues and has been reported to adopt a mixed 3(10)/α-helical conformation using circular dichroism and nuclear magnetic resonance spectroscopy studies.
authors: Malaria Lab, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors: Madhvi Gupta
authors: MG
authors: Dutta
authors: Puniti
authors: P
authors: Mathur
authors: Virander S
authors: VS
authors: Chauhan
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D055550:Protein Stability; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000596:Amino Acids; D009842:Oligopeptides; D010649:Phenylalanine; C018632:phenyldehydroalanine