Extreme stability of an unsolvated alpha-helix.
High-temperature ion mobility measurements have been performed for alpha-helical Ac-A15K+H+ and globular Ac-KA15+H+ peptides. The alpha-helical and globular conformations do not melt into random coils as the temperature is raised. Instead, both conformations survive to the point where the peptide signals vanishes due to fragmentation. This occurs at 600 K for the globular Ac-KA15+H+ peptide and at 725 K for the alpha-helical Ac-A15K+H+. For the helical Ac-A15K+H+ peptide it appears that fragmentation is triggered by disruption of the helical conformation.
Kohtani
Motoya
M
Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
Jones
Thaddeus C
TC
Schneider
Jean E
JE
Jarrold
Martin F
MF
D000409:Alanine / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013696:Temperature
D010455:Peptides; D008239:Lysine; D000409:Alanine