Enhancement of ultraviolet photodissociation efficiencies through attachment of aromatic chromophores.
Two N-terminal derivatization reagents containing aromatic chromophores, 4-sulfophenyl isothiocyanate (SPITC) and 4-methylphosphonophenyl isothiocyanate (PPITC), were used to increase the dissociation efficiencies of peptides upon ultraviolet photodissociation (UVPD) at 193 nm. The resulting UVPD spectra are dominated by C-terminal ions, including y, z, x, v, and w ions, and immonium ions. The attachment of the PPITC or SPITC groups leads to a reduction in the number and abundances of N-terminal ions because the added phosphonate or sulfonate functionalities result in neutralization of some of the N-terminal species, ones that might normally be singly protonated in the absence of the negatively charged sulfonate or phosphonate groups. In addition, the greater photoabsorptivities of the PPITC- and SPITC-derivatized N-terminal product ions enhanced their secondary photodissociation, leading to formation of immonium ions.
Vasicek
Lisa
L
Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, United States.
Brodbelt
Jennifer S
JS
D000595:Amino Acid Sequence; D000818:Animals; D001557:Benzenesulfonates / Q000737:chemistry*; D002417:Cattle; D003124:Colorimetry; D017879:Isothiocyanates / Q000737:chemistry*; D008969:Molecular Sequence Data; D063065:Organophosphonates / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D055668:Photochemical Processes; D014357:Trypsin / Q000378:metabolism; D014466:Ultraviolet Rays
C543135:4-methylphosphonophenylisothiocyanate; D001557:Benzenesulfonates; D017879:Isothiocyanates; D063065:Organophosphonates; D010455:Peptides; C015308:4-isothiocyanatobenzenesulfonate; D014357:Trypsin