Ultraviolet Photodissociation Mass Spectrometry for Analysis of Biological Molecules

Abstract

The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review. CONTENTS 1. Introduction 3328 1.1. Scope of Review 3328 1.2. Instrumentation 3330 2. UVPD for Peptides 3330 2.1. Mechanistic Studies of Peptides 3330 2.2. UVPD for Peptide Sequencing and Bottom-Up Proteomics 3332 2.3. UVPD for Identification of Post-Translational Modifications 3333 2.4. PTM Analysis Using Other Wavelengths 3336 2.5. Improving S/N of UVPD 3336 2.6. UVPD and Derivatization Strategies 3337 2.6.1. Radical-Directed Dissociation 3337 2.6.2. Photoelectron-Transfer Dissociation 3340 2.6.3. UVPD (266 nm) for Selective Bond Cleavages 3340 2.6.4. UVPD Using 351/355 nm Photons 3340 2.6.5. UVPD with Online Reactions and Hydrogen/Deuterium Exchange 3342 2.6.6. Derivatization and Photodissociation Using Visible Wavelengths 3343 2.7. UVPD for Middle-Down Proteomics 3343 3. UVPD for Intact Proteins 3345 3.1. Fundamental Aspects 3347 3.2. Hybrid Methods and New Concepts for Top-Down Analysis 3347 3.3. Other Wavelengths for Top-Down Analysis 3351 4. UVPD for Native Mass Spectrometry and Structural Biology Applications 3352 4.1. Chemical-Probe Methods 3352 4.2. Native MS 3354 4.2.1. Protein−Ligand Complexes 3355 4.2.2. UVPD for Multimeric Protein Complexes 3357 4.3. UVPD and Ion Mobility 3359 5. UVPD for Lipids 3360 5.1. Radical-Directed Dissociation 3360 5.2. UVPD (193 nm) 3361 5.3. UVPD (213 nm) 3362 5.4. UVPD and DESI 3364 5.5. Lipid A and Lipopolysaccharides 3364 6.

Recent developments in the characterization of nucleic acids by liquid chromatography, capillary electrophoresis, ion mobility, and mass spectrometry (2010–2020)

“…Ultraviolet photodissociation (UVPD) is a fast, high‐energy activation process that primarily causes detachment of an electron prior to extensive fragmentation. UVPD has most commonly been undertaken using custom‐modified commercial mass spectrometers, mainly ion trap systems, where the laser is guided by mirrors and introduced via an optical window into the ion trapping cell [55]. Due to this reason, UVPD has been explored by relatively few academic research groups and has not been widely adopted by the broader scientific community.…”

Sequential Ion-Ion Reactions for Enhanced Gas-Phase Sequencing of Large Intact Proteins in a Tribrid Orbitrap Mass Spectrometer

“…This is also a known issue in UVPD MS 2 spectra where distribution of m/z values for the larger mass product ions are primarily centered around the intact precursor m/z. 7 Gas-phase fractionation (GPF) is an approach that has been utilized to improve detection of proteoforms 36 and also to enhance the performance of imaging mass spectrometry; 37 therefore, its application could also be beneficial for improving the quality of MS 2 spectra of whole proteoforms. However, GPF could increase spectral dynamic range but would not solve the signal interference problem.…”

Conformational analysis by UV spectroscopy: the decisive contribution of environment-induced electronic Stark effects

“…their fragmentation pattern using mass spectrometry. 6 A higher spectral resolution can sometimes be decisive to directly identify conformers by measuring the rotational contour of their electronic transition. 7,8 For relatively simple systems, UV spectra with full rotational resolution can be recorded and provide unambiguous conformational assignments.…”