Combination of High-Resolution Multistage Ion Mobility and Tandem MS with High Energy of Activation to Resolve the Structure of Complex Chemoenzymatically Synthesized Glycans

Comprehensive profiling and development of a collision cross section database for milk oligosaccharides via orthogonal UPLC-cyclic ion mobility-mass spectrometry system

Human milk oligosaccharides (HMOs) have attracted immense interest in the infant formula industry for their health benefits. Herein, we utilized liquid chromatography-cyclic ion mobility-mass spectrometry (LC-cIM-MS) to develop a robust and multidimensional HMO profiling workflow. This workflow relies on a self-built glycan library, allowing high-throughput searching of oligosaccharides. cIM-MS demonstrated high resolving power in discriminating glycan isomers and increasing peak capacity. This also facilitated the accurate elucidation of most oligosaccharides at sequence levels. A remarkably diverse milk oligosaccharide profile (n = 98) was observed and enabled the discovery of distinctive chromatographic retention patterns. To provide supplementary selectivity for future routine assignment in the absence of standards, we further developed a comprehensive database of experiment-derived traveling wave collision cross section in nitrogen (TWCCSN2) for 98 HMOs, including isomer-resolved TWCCSN2 values. Finally, the profile revealed 64 oligosaccharides unique to human milk compared with infant formula, indicating the potential ingredients for formula improvement.

Pharmacokinetics, tissue distribution and metabolism of hydroxyethyl starch 130/0.4 in rats

Hydroxyethyl starch (HES) is a clinically utilized polymeric polysaccharide commonly administered intravenously to achieve the pharmacologic effects of maintaining circulating blood volume and improving microcirculation. Its plasma pharmacokinetics, metabolism, and biodistribution are essential for assessing effectiveness and adverse effects. However, the identification of metabolites and direct quantification of HES in vivo present significant challenges due to its complex molecular structure and polydispersity. In this study, we introduce a novel approach to analyzing the pharmacokinetics of HES in rats using liquid chromatography-mass spectrometry, with hydroxyethyl starch 130/0.4 (HES130/0.4) as a model. The findings indicate that HES130/0.4 undergoes rapid metabolism following intravenous administration, predominantly through glycosidic bond cleavage. The molecular weights of the identified metabolites in plasma and urine ranged from 500 to 3400 Da. Metabolites below the renal threshold are preferentially excreted via the kidneys, whereas the macromolecule HES130/0.4 exhibits a large apparent volume of distribution and is cleared from the plasma within 24 h. High concentrations of HES130/0.4 were observed in highly perfused tissues, nonetheless, the metabolism and elimination of HES130/0.4 within tissues occur at a slower rate, posing a risk of tissue accumulation. This study represents the first accurate characterization of the in vivo fate of HES130/0.4, providing a critical foundation for evaluating its efficacy and safety. Furthermore, it establishes a methodological framework for the bioanalysis and comprehensive elucidation of the in vivo fate of other HES variants.

Installation protocol for charge transfer dissociation mass spectrometry on ion trapping mass spectrometers

RATIONALE

Charge transfer dissociation (CTD) is a novel fragmentation technique that demonstrates enhanced structural characterization for a wide variety of molecules compared to standard fragmentation techniques like collision-induced dissociation (CID). Alternative fragmentation techniques, such as electron transfer dissociation, electron capture dissociation, and ultraviolet photodissociation, also overcome many of the shortfalls of CID, but none of them are a silver bullet that can adequately characterize a wide variety of structures and charge states of target compounds. Given the diversity of structural classes and their occasional obstinance towards certain activation techniques, alternative fragmentation techniques are required that rely on novel or alternative modes of activation.

METHODS

Herein, we present a step-by-step protocol for the installation of CTD on a quadrupole ion trap mass spectrometer and best practices for optimizing the signal-to-noise ratio and acquisition times for CTD mass spectra.

RESULTS

In addition to two CTD installations in the Jackson laboratory, CTD has also been installed, and is currently in operation, on two 3D ion trap mass spectrometers in France: one in the laboratory of Dr. David Ropartz and Dr. Hélène Rogneaux at INRAE in Nantes, and the other in the laboratory of Dr. Jean-Yves Salpin at Université d'Évry Val-d'Essonne, part of the Paris-Saclay University system.

CONCLUSIONS

Here, we provide a visual protocol to help others accomplish the instrument modification.

Recent chemical synthesis and immunological evaluation of glycans related to bacterial lipopolysaccharides

O-Antigens and core oligosaccharides from bacterial lipopolysaccharides (LPS) are often structurally unique and immunologically active, have become attractive targets in the development of antibacterial vaccines. Structurally well-defined and pure oligosaccharides can be used in identifying protective epitopes of the carbohydrate antigens, which is important for the design of an effective vaccine. Here, the recent progress on chemical synthesis and immunological evaluation of glycans related to O-antigens and core oligosaccharides from bacterial LPS are summarized.

Enhancing the Depth of Analyses with Next-Generation Ion Mobility Experiments

Recent developments in ion mobility (IM) technology have expanded the capability to separate and characterize gas-phase ions of biomolecules, especially when paired with mass spectrometry. This next generation of IM technology has been ushered in by creative innovation focused on both instrument architectures and how electric fields are applied. In this review, we focus on the application of high-resolution and multidimensional IM to biomolecular analyses, encompassing the fields of glycomics, lipidomics, peptidomics, and proteomics. We highlight selected research that demonstrates the application of the new IM toolkit to challenging biomolecular systems. Through our review of recently published literature, we outline the current strengths of respective technologies and perspectives for future applications.

Gas-Phase Behavior of Galactofuranosides upon Collisional Fragmentation: A Multistage High-Resolution Ion Mobility Study

Carbohydrates are ubiquitous in nature but are among the least conserved biomolecules in life. These biopolymers pose a particular challenge to analytical chemists because of their high diversity and structural heterogeneity. In addition, they contain many isomerisms that complicate their structural characterization, notably by mass spectrometry. The tautomerism of the constitutive subunits is of particular interest. A given cyclized monosaccharide unit can take two forms: a most common 6-membered ring (pyranose, p) and a more flexible 5-membered ring (furanose, f). The tautomers impact the biological properties of polysaccharides, resulting in interesting properties of the derived oligosaccharides. From an analytical point of view, the impact of tautomerism on the gas-phase behavior of ions has scarcely been described in the literature. In this work, we study the behavior of Galf-containing oligosaccharides, ionized as [M+Li]⁺ species, under collisional dissociation (CID) conditions using high-resolution and multistage ion mobility (IMS) on a Cyclic IMS platform. In the first part of this work, we studied whether disaccharidic fragments released from Galf-containing (Gal)₁(Man)₂ trisaccharides (and their Galp counterpart) would match the corresponding disaccharide standards, and─despite the fragments generally being a good match─we showed the possibility of Galf migrations and other unidentified alterations in the IMS profile. Next, we expanded on these unknown features using multistage IMS and molecular dynamics, unveiling the contributions of additional gas-phase conformers in the profile of fragments from a Galf-containing trisaccharide compared with the corresponding disaccharides.