New tools for the control of peptide conformation: the helicogenic Cα-methyl, Cα-cyclohexylglycine

• Published in: The journal of peptide research Vol. 63; no. 2; pp. 161 - 170
• Main Authors: Formaggio, F., Moretto, V., Crisma, M., Toniolo, C., Kaptein, B., Broxterman, Q.B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2004; Wiley
• Subjects: 310-helix; amino acid synthesis; Biochemical Research Methods; Biochemistry & Molecular Biology; Cα-tetrasubstituted α-amino acid; Life Sciences & Biomedicine; peptide synthesis; Science & Technology; spectroscopy; X-ray diffraction; β-turn; LINEAR OLIGOPEPTIDES; beta-turn; C alpha-tetrasubstituted alpha-amino acid; X-ray diffraction; POLYPEPTIDES; HYDROGEN-BOND DISTANCES; MOLECULES; TURNS; 3-helix; spectroscopy; AMINO-ACIDS; ANGLES; STRUCTURAL CHARACTERISTICS; MAGNETIC-RESONANCE; amino acid synthesis; HOMOPEPTIDES; peptide synthesis
• ISSN: 1397-002X; 1399-3011
• DOI: 10.1111/j.1399-3011.2003.00123.x

:  The novel Cα‐tetrasubstituted α‐amino acid Cα‐methyl, Cα‐cyclohexylglycine was prepared by hydrogenation of its Cα‐methyl, Cα‐phenylglycine precursor. Terminally protected homodi‐, homotri‐, and homotetrapeptides from Cα‐methyl, Cα‐cyclohexylglycine and co‐oligopeptides to the pentamer level in combination with Gly or α‐aminoisobutyric acid residues were prepared by solution methods and fully characterized. The results of a conformational analysis, performed by use of Fourier transform infrared (FT‐IR) spectrophotomet absorption, 1H NMR, and X‐ray diffraction techniques, support the contention that this Cα‐methylated, Cβ‐trisubstituted aliphatic α‐amino acid is an effective β‐turn and 310‐helix inducer in tri‐ and longer peptides as its Cα‐methyl valine parent compound, but partially divergent from the corresponding aromatic Cα‐methyl, Cα‐diphenylmethylglycine residue, known to promote folded and fully extended structures to a significant extent in these oligomers.