UV Photofragmentation Dynamics of Protonated Cystine: Disulfide Bond Rupture

作者：Soorkia Satchin^*; Dehon Christophe; Kumar S Sunil; Pedrazzani Melanie; Frantzen Emilie; Lucas Bruno; Barat Michel; Fayeton Jacqueline A; Jouvet Christophe

来源：Journal of Physical Chemistry Letters, 2014, 5(7): 1110-1116.

DOI：10.1021/jz500158j

Disulfide bonds (S-S) play a central role in stabilizing the native structure of proteins against denaturation. Experimentally, identification of these linkages in peptide and protein structure characterization remains challenging. UV photodissociation (UVPD) can be a valuable tool in identifying disulfide linkages. Here, the S-S bond acts as a UV chromophore and absorption of one UV photon corresponds to a sigma-sigma* transition. We have investigated the photodissociation dynamics of protonated cystine, which is a dimer of two cysteines linked by a disulfide bridge, at 263 nm (4.7 eV) using a multicoincidence technique in which fragments coming from the same fragmentation event are detected. Two types of bond cleavages are observed corresponding to the disulfide (S-S) and adjacent C-S bond ruptures. We show that the S S cleavage leads to three different fragment ions via three different fragmentation mechanisms. The UVPD results are compared to collision-induced dissociation (CID) and electron-induced dissociation (EID) studies.

• 出版日期2014-4-3