The complete chirospectroscopic signature of the peptide 3(10)-helix in aqueous solution.
We synthesized by solution methods a water-soluble, terminally blocked heptapeptide based on five markedly helicogenic, C(alpha)-tetrasubstituted alpha-amino acids C(alpha)-methyl-L-norvalines and two strongly hydrophilic 2-amino-3-[1-(1,4,7-triazacyclononane)]-L-propanoic acid residues at positions 2 and 5. A Fourier transform infrared absorption and NMR analysis in deuterated chloroform and aqueous solutions of the heptapeptide and two side-chain protected synthetic precursors confirmed our working hypothesis that all oligomers are folded in the 3(10)-helical conformation. Based on these findings, we exploited this heptapeptide as a chiral reference compound for detailed electronic CD, vibrational CD, and Raman optical activity characterizations of the 3(10)-helix in aqueous solution.
Department of Chemistry, University of Padova, 35131 Padova, Italy. claudio.toniolo@unipd.it
Claudio
C
Toniolo
Fernando
F
Formaggio
Sabrina
S
Tognon
Quirinus B
QB
Broxterman
Bernard
B
Kaptein
Rong
R
Huang
Vladimir
V
Setnicka
Timothy A
TA
Keiderling
Iain H
IH
McColl
Lutz
L
Hecht
Laurence D
LD
Barron
D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013237:Stereoisomerism
D009842:Oligopeptides