The Mechanism Behind Top-Down UVPD Experiments: Making Sense of Apparent Contradictions

• Published in: Journal of the American Society for Mass Spectrometry Vol. 28; no. 9; pp. 1823 - 1826
• Main Author: R Julian, Ryan
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2017; Springer Nature B.V
• Subjects: Analytical Chemistry; Bioinformatics; Biotechnology; Chemistry; Chemistry and Materials Science; Covalence; Covalent bonds; Critical Insight; Fracturing; Mass spectrometry; Organic Chemistry; Photochemistry; Photodissociation; Proteins; Proteomics; Ultraviolet; Top-down proteomics; 266 nm; Direct dissociation; Internal conversion; 193 nm
• ISSN: 1044-0305; 1879-1123; 1879-1123
• DOI: 10.1007/s13361-017-1721-0

Top-down ultraviolet photodissociation (UVPD) allows greater sequence coverage than any other currently available method, often fracturing the vast majority of peptide bonds in whole proteins. At the same time, UVPD can be used to dissociate noncovalent complexes assembled from multiple proteins without breaking any covalent bonds. Although the utility of these experiments is unquestioned, the mechanism underlying these seemingly contradictory results has been the subject of many discussions. Herein, some fundamental considerations of photochemistry are briefly summarized within the context of a proposed mechanism that rationalizes the experimental results obtained by UVPD. Considerations for future instrument design, in terms of wavelength choice and power, are briefly discussed. Graphical Abstract ᅟ