Recent Publications
Photoactivation at 266 nm of the carbon-iodine bond yields dissociation bond specific dissociation and the formation of a radical at the site of modification. Subsequent collisional activation results in radical mediated dissociation.
Deamdiation of asparagine proceeds through an intramolecular nucleophilic attack resulting in a succinimide ring intermediate. This intermediate is prone to racemization and hydrolysis, yielding four possible isomers of aspartic acid.
Selective dissociation of disulfide bonds with ultraviolet photodissociation at 266nm in the gas phase. All other bonds are left intact, allowing the identification of disulfide bonded pairs in complex systems with multiple disulfide bond partners.
Does Data-Independent Acquisition Data Contain Hidden Gems? A Case Study Related to Alzheimer's Disease. Evan E. Hubbard, Lilian R. Heil, Gennifer E. Merrihew, Jasmeer P. Chhatwal, Martin R. Farlow, Catriona A. McLean, Bernardino Ghetti, Kathy L. Newell, Matthew P. Frosch, Randall J. Bateman, Eric B. Larson, C. Dirk Keene, Richard J. Perrin, Thomas J. Montine, Michael J. MacCoss, and Ryan R. Julian. Journal of Proteome Research, 2021. DOI: 10.1021/acs.jproteome.1c00558.
Proteolysis of Amyloid β by Lysosomal Enzymes as a Function of Fibril Morphology. Tyler R. Lambeth, Ryan R. Julian. ACS Omega, 2021, 6, 47, 31520–31527. DOI: 10.1021/acsomega.1c03915.
Efficient Isothiocyanate Modification of Peptides Facilitates Structural Analysis by Radical-Directed Dissociation. Tyler R. Lambeth, Ryan R. Julian. Journal of the American Society for Mass Spectrometry. 2021, jasms.1c00237. DOI: 10.1021/jasms.1c00237.
A Two-Trick Pony: Lysosomal Protease Cathepsin B Possesses Surprising Ligase Activity. Tyler R. Lambeth, Zhefu Dai, Yong Zhang, Ryan R. Julian. RSC Chemical Biology, 2021, 2 (2), 606–611 DOI: 10.1039/d0cb00224k.
Probing the Stability of Proline Cis/Trans Isomers in the Gas Phase with Ultraviolet Photodissociation. Jacob W. Silzel, Taylor A. Murphree, Rajan K. Paranji, Miklos M. Guttman, Ryan R. Julian. Journal of the American Society for Mass Spectrometry. 2020, 31 (9), 1974–1980 DOI: 10.1021/jasms.0c00242
Differentiation of Peptide Isomers by Excited-State Photodissociation and Ion-Molecule Interactions. Brielle L. Van Orman, Hoi Ting Wu, Ryan R. Julian. Phys. Chem. Chem. Phys. 2020, 22 (41), 23678–23685. DOI: 10.1039/d0cp04111d
Two-Dimensional Identification and Localization of Isomers in Crystallin Peptides Using TWIM-MS. Hoi Ting Wu, Ryan R. Julian. Analyst 2020, 145 (15), 5232–5241. DOI: 10.1039/d0an01036g
Synthesis of New SS and CC Bonds by Photoinitiated Radical Recombination Reactions in the Gas Phase. Lance E. Talbert, Xing Zhang, Nathan Hendricks, Arman Alizadeh, Ryan R Julian. International Journal of Mass Spectrometry, 2019 DOI: 10.1016/j.ijms.2019.04.002
Spontaneous Isomerization of Long-Lived Proteins Provides a Molecular Mechanism for the Lysosomal Failure Observed in Alzheimer's Disease. Tyler R. Lambeth, Dylan L. Riggs, Lance E. Talbert, Jin Tang, Emily Coburn, Amrik S. Kang, Jessica Noll, Catherine Augello, Byron D. Ford, Ryan R. Julian. ACS Central Science 2019, 5 (8), 1387-1395. DOI: 10.1021/acscentsci.9b00369
Directed-Backbone Dissociation Following Bond-Specific Carbon-Sulfur UVPD at 213 nm. Lance E. Talbert, Ryan R. Julian. Journal of The American Society for Mass Spectrometry, 2018, 29 (9), 1760-1767 DOI:10.1007/s13361-018-1934-x
Simplified Identification of Disulfide, Trisulfide, and Thioether Pairs With 213 nm UVPD. James Bonner, Lance E. Talbert, Nicholas Akkawi, Ryan R. Julian. Analyst, 2018, 143, 5176-5184 DOI:10.1039/C8AN01582A
Differences in Alpha-Crystallin Isomerization Reveal the Activity of Protein Isoaspartyl Methyltransferase (PIMT) in the Nucleus and Cortex of Human Lenses. Yana A. Lyon, Georgette M. Sabbah, Ryan R. Julian. Experimental Eye Research, 2018, 171, 131-141 DOI:10.1016/j.exer.2018.03.018
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(a) Photoactivation of DRVYIIHPF at 213 nm, yielding dominant loss of iodine radical. (b) Zoom in of minor losses from (a). (c) Photoactivation of unmodified DRVYIHPF at 213 nm, yielding similar nonspecific fragments.
(a) LCMS chromatogram of the 4IB-VKLDSG deamidation products, which yields only two chromatographic peaks. (b–e) RDD tandem mass spectra on [4IB-VKLDSG + H]1+ from the leading and trailing edges of the peaks in panel a show differences in fragment intensities that reveal coeluting isomers within both peaks.