High-Energy Collision-Induced Dissociation by MALDI TOF/TOF Causes Charge-Remote Fragmentation of Steroid Sulfates

Abstract

A method for structural elucidation of biomolecules dating to the 1980s utilized high-energy collisions (~10 keV, laboratory frame) that induced charge-remote fragmentations (CRF), a class of fragmentations particularly informative for lipids, steroids, surfactants, and peptides. Unfortunately, the capability for high-energy activation has largely disappeared with the demise of magnetic sector instruments. With the latest designs of tandem time-of-flight mass spectrometers (TOF/TOF), however, this capability is now being restored to coincide with the renewed interest in metabolites and lipids including steroid-sulfates and other steroid metabolites. For these metabolites, structure determinations are required at concentration levels below that appropriate for NMR. To meet this need, we explored CRF with TOF/TOF mass spectrometry for two groups of steroid sulfates, 3-sulfates and 21-sulfates. We demonstrated that the current generation of MALDI TOF/TOF instruments can generate charge-remote-fragmentations for these materials. The resulting collision-induced dissociation (CID) spectra are useful for positional isomer differentiation and very often allow the complete structure determination of the steroid. We also propose a new nomenclature that directly indicates the cleavage sites on the steroid ring with carbon numbers.

Aglycon diversity of brain sterylglucosides: structure determination of cholesteryl- and sitosterylglucoside

“…2C) . The charge remote fragmentation pattern matched the fingerprint of the Chol standard (23), with the expected constant shift of 162 Da (Fig. 2D) supporting the presence of a sterylhexoside.…”

“…Fragment ions of the main component corresponded well to the expected GlcChol, while the two minor components exhibited an increased mass, greater by 14 and 28 Da. Charge-mediated as well as chargeremote fragmentation (24) of the further-purified main component and Chol standard by MALDI-Spiral TOF/ TOF and Fourier transform ion cyclotron resonance mass spectrometry (23,25), together with GC/MS analysis of the liberated aglycon, confirmed the presence of a -cholesteryl residue. Complete superposition of the 2D NMR spectral data from natural and authentic GlcChol proves that a glucopyranoside residue is present and is linked via a -glycosidic linkage to a -cholesteryl aglycon.…”

Ozone‐induced dissociation on a traveling wave high‐resolution mass spectrometer for determination of double‐bond position in lipids

“…Under the environment of high concentration ozone, the vinyl peroxide ion lost formaldehyde (H 2 CO) to form the unique product observed. This has similar mass to the direct C=C cleavage product ( m/z 636.4599) generated using a high‐energy collision (~10 keV) either on magnetic sector or TOF/TOF instruments . Because of the low collision energy in our OzID experiments (4 eV) and the high mass measurement accuracy of the Synapt G2, we were able to assign the product ions correctly as the further oxidation product of vinyl peroxide (theoretical mass 636.4240), not the C=C bond direct cleavage.…”

“…On the other hand, the commonly used low‐energy collision‐induced dissociation (CID)‐MS is able to assign the sn‐ positions and, identify the total number of carbons on each fatty acyl chain along with their total degree of unsaturation from intact lipids, but struggles to characterize the locations of double bonds without using multistage ion activation techniques on lipid‐metal adduct ions . Alternatively, high‐energy CID‐MS has been applied to study the structural variation of the fatty acyl chains, yielding a highly complicated fragmentation spectrum embedded with structurally diagnostic product ions …”

Screening and identification of serum biomarkers of osteoarticular tuberculosis based on mass spectrometry

“…They have shown many advantages such as fast detection speed and accurate results in blood, body fluid, and colony samples. 11,21,22 There have also been studies on tuberculosis using the above-mentioned mass Combined with the ROC curve of the corresponding model, these diagnostic models can better distinguish osteoarticular tuberculosis from other diseases and thus, provide good diagnostic results. In order to make the diagnostic model more accurate, we will in future use the advantages of a multi-center study to expand the number of samples for verification.…”