Fragmentation of protonated peptides: surface-induced dissociation in conjunction with a quantum mechanical approach (original) (raw)

1993, Analytical Chemistry

This paper describes the results of a systematic investigation designed to assess the utility of surface-induced dissociation in the structural analysis of small peptides (500-1800~). A number of different peptides, ranging in mass and amino acid sequence, are fragmented by collision with a surface in a tandem mass spectrometer and the spectra are compared with data obtained by gasphase collisional activation. The surface-induced dissociation spectra provide ample sequence information for the peptides. Side-chain cleavage ions of type w, which are generally detected upon kiloelectronvolt collisions with gaseous targets but not upon electronvolt collisions with gaseous targets, are detected in the ion-surface collision experiments. A theoretical approach based on MNDO bond order calculations is suggested for the description of peptide fragmentation. This model, supplemented by ab initio calculations, serves as a complement to the experimental work described in the paper and explains (i) the easy cleavage of the amide bond, (ii) charge-remote backbone and side-chain cleavages, and (iii) the influence of intramolecular H-bonding. t Present addrm: (39) Winger, B. E.; Laue, H.-J.; Homing, 5. R.; Julian, R. K., Jr.; Lammert, S. A.; Riederer, D. E., Jr.; Cooks, R. G.Rev. Sci. Instrum. 1992, (40) Beck, R. D.; St. John, P.; Alvarez, M. M.; Diederich, F.; Whetten, R. L. J. Phys. Chem. 1991,95, 8402-8409. (41) St. John, P. M.; Whetten, R. L. Chem. Phys. Lett. 1992, 196, 330-336. (42) Somogy,A.;Kane,T.E.;Ding,J.-M.;Wysocki,V.H.