Cyclic peptide as reference system for b ion structural analysis in the gas phase.
Infrared multiple photon dissociation spectroscopy and hydrogen/deuterium exchange methods are used to confirm the macrocylic structure of a b(6) peptide fragment by direct comparison with a synthetically made cyclic peptide. The acetylation of the peptide N-terminus results in the inhibition of the macrocyclic formation, supporting the "head-to-tail" cyclization mechanism. Differences in hydrogen/deuterium exchange rates for macrocyclic and oxazalone structure peptide fragments are interpreted to be a result of the complex interplay of multiple basic sites in the peptide fragment, supporting the relay mechanism for deuterium exchange with CH(3)OD.
Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.
Xian
X
Chen
Marcus
M
Tirado
Jeffrey D
JD
Steill
Jos
J
Oomens
Nick C
NC
Polfer
D003500:Cyclization; D041961:Deuterium Exchange Measurement; D005740:Gases / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D047028:Macrocyclic Compounds / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D005740:Gases; D007477:Ions; D047028:Macrocyclic Compounds; D010446:Peptide Fragments; D010456:Peptides, Cyclic