Charge-state resolved mid-infrared spectroscopy of a gas-phase protein.
Infrared spectra of a 104 amino-acid protein in the gas phase as a function of its charge state are presented. The spectra contain clearly resolvable bands in the amide I and II spectral regions, as well as a band at 1483 cm(-1), which is not observed in solution phase spectroscopy and is especially prominent for the higher charge states. Compared to solution, the amide I band is blue-shifted and the amide II band red-shifted, as expected for species in an environment with reduced hydrogen bonding. The band positions are suggestive of a mostly alpha-helical structure of the protein and their widths are comparable to those in solution, suggesting a similar conformational distribution.
FOM Institute for Plasma Physics Rijnhuizen, Edisonbaan 14, NL-3439 MN Nieuwegein, The Netherlands.
Jos
J
Oomens
Nick
N
Polfer
David T
DT
Moore
Lex
L
van der Meer
Alan G
AG
Marshall
John R
JR
Eyler
Gerard
G
Meijer
Gert
G
von Helden
D000577:Amides / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D005740:Gases / Q000737:chemistry*; D006860:Hydrogen Bonding; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D012996:Solutions; D013055:Spectrophotometry, Infrared / Q000379:methods; D055672:Static Electricity
D000577:Amides; D000596:Amino Acids; D005740:Gases; D011506:Proteins; D012996:Solutions