Gas-phase conformation-specific photofragmentation of proline-containing peptide ions.
Singly-protonated proline-containing peptides with N-terminal arginine are photodissociated with vacuum ultraviolet (VUV) light in an ESI linear ion trap/orthogonal-TOF (LIT/o-TOF). When proline is the nth residue from the N-terminus, unusual b(n) + 2 and a(n) + 2 ions are observed. Their formation is explained by homolytic cleavage of the C(alpha)-C bond in conjunction with a rearrangement of electrons and an amide hydrogen. The latter is facilitated by a proline-stabilized gas-phase peptide conformation.
Kim
Tae-Young
TY
Department of Chemistry, Indiana University, Bloomington, Indiana, USA.
Valentine
Stephen J
SJ
Clemmer
David E
DE
Reilly
James P
JP
D001120:Arginine / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry*; D055668:Photochemical Processes; D011392:Proline / Q000737:chemistry*; D011487:Protein Conformation; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014466:Ultraviolet Rays
D007477:Ions; D010455:Peptides; D001120:Arginine; D011392:Proline