A multicenter phase II trial of the triplet antiemetic therapy with palonosetron, aprepitant, and olanzapine for a cisplatin-containing regimen. - PATROL-I.

Dexamethasone is one of the key antiemetic agents and is widely used even now. However, dexamethasone has been associated with several adverse reactions even after short-term administration. Therefore, developing a steroid-free antiemetic regimen is an important issue to consider. Thus, the purpose of this study was to investigate the efficacy and safety of palonosetron, aprepitant, and olanzapine in a multi-institutional phase II study. Chemotherapy-naive patients scheduled to receive cisplatin were enrolled and evaluated for the occurrence of chemotherapy-induced nausea and vomiting during 120 h after chemotherapy. The primary endpoint of the study was total control (TC) in the overall phase. The key secondary endpoint was complete response (CR), which was assessed in the acute, delayed, and overall phase, respectively. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events. Eighty-five patients were enrolled from 8 centers in Japan, of which 83 were evaluable for analyses. The percentage of patients who achieved TC during the overall phase was 31.3%. CR was achieved in 61.4%, 84.3%, and 65.1% of patients during the overall, acute, and delayed phases, respectively. The most frequently reported adverse event was anorexia. The primary endpoint was below the threshold and we could not find benefit in the dexamethasone-free regimen, but CR during the overall phase was similar to that of the conventional three-drug regimen. This antiemetic regimen without dexamethasone might be an option for patients for whom corticosteroids should not be an active application.

[Understanding public health nurses' experience, knowledge, and perception of bioterrorism training in Japan].

Objectives　Bioterrorism is a disease in which the attacks can be covert and latent, take time to manifest, and, when discovered, can result in large outbreaks. When detected, they can become large-scale outbreaks. Therefore, preparedness is essential for early detection and response for damage mitigation. Although public health nurses (PHNs) of public health centers are responsible for detecting and dealing with bioterrorism, their preparation status is not clear. Therefore, this study aimed to elucidate the status of training experience, knowledge, and awareness of bioterrorism among PHNs working in public health centers' infectious disease control departments in Japan's metropolitan areas.Methods　This was a cross-sectional, descriptive study. The participants were PHNs in the infectious disease control departments of 88 public health centers in Tokyo and its three neighboring prefectures. This are densely populated metropolitan areas with many mass gathering events and a high probability of bioterrorism. An anonymous, self-administered questionnaire survey was conducted by mail in 2019. Two PHNs per location were surveyed regarding their attributes, training experience, knowledge, and perceptions.Results　We received 71 responses (40.3%). A total of 10 (14.1%) PHNs reported having experience with bioterrorism training in the workplace. Regarding the knowledge of the four infectious diseases with a high probability of bioterrorism, more than 95% of the respondents answered they had heard of them. However, few were aware of related treatments or terrorist responses. Although survey respondents were aware of the seriousness of bioterrorism and the effectiveness of preparedness, they did not have sufficient opportunity or time to have training. They tended to be less confident in their response and were willing to have training.Conclusion　PHNs who responded to this survey do not have sufficient training experience, knowledge, opportunities, and time for bioterrorism training, and establishing a training system to improve bioterrorism preparedness is a challenge. It will be necessary for PHN students to learn about the existence of bioterrorism. Further, PHNs in public health centers need to be trained at least once using online services, including brushing up on information as needed. Based on the lessons learned from the coronavirus disease 2019 pandemic, health centers will formulate a Health Crisis Management Plan. This will be effective in fiscal 2024, and we believe that it is essential that preparedness against bioterrorism be a part of this plan.

Severity of SARS-CoV-2 infection in pregnant women and their neonates during the Omicron period compared to the pre-Omicron period: A retrospective cohort study.

AIM: To compare the clinical outcomes among women diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy, and their neonates, during the period when the Omicron variant predominated in Japan with those of the pre-Omicron variant period. METHODS: We conducted a retrospective single-center cohort study between August 1, 2020, and June 30, 2022. The cohort was divided into pre-Omicron group (August 1, 2020 to November 30, 2021) and Omicron group (December 1, 2021 to June 30, 2022). The primary outcome was maternal intensive care unit (ICU) admission during the perinatal period. The secondary outcomes were maternal oxygen administration before and after delivery, preterm birth (PTB), and low birth weight (LBW). RESULTS: During the study period, 81 pregnant women were admitted to the hospital with SARS-CoV-2 infection (pre-Omicron period, n = 28; Omicron period, n = 53). SARS-CoV-2 infection during the Omicron period was associated with lower risk of maternal ICU admission (adjusted-odds ratio [aOR]: 0.10, 95% confidence interval [CI]: 0.01-1.23, p = 0.072), oxygen administration via a nasal cannula or mask (aOR: 0.18, 95% CI: 0.03-0.96, p = 0.045), PTB (aOR: 0.15, 95% CI: 0.04-0.51, p = 0.002), and LBW (aOR: 0.13, 95% CI: 0.03-0.55, p = 0.005). CONCLUSION: Among pregnant women, SARS-CoV-2 infection during the Omicron period was associated with reduced risk of maternal ICU admission, requiring supplemental oxygen, PTB, and LBW. This can be attributable to lower virulence of the Omicron variant and higher vaccination coverage during the Omicron period.

Experimental and computational characterization of dynamic biomolecular interaction systems involving glycolipid glycans.

On cell surfaces, carbohydrate chains that modify proteins and lipids mediate various biological functions, which are exerted not only through carbohydrate-protein interactions but also through carbohydrate-carbohydrate interactions. These glycans exhibit considerable degrees of conformational variability and often form clusters providing multiple binding sites. The integration of nuclear magnetic resonance spectroscopy and molecular dynamics simulation has made it possible to delineate the dynamical structures of carbohydrate chains. This approach has facilitated the remodeling of oligosaccharide conformational space in the prebound state to improve protein-binding affinity and has been applied to visualize dynamic carbohydrate-carbohydrate interactions that control glycoprotein-glycoprotein complex formation. Functional glycoclusters have been characterized by experimental and computational approaches applied to various model membranes and artificial self-assembling systems. This line of investigation has provided dynamic views of molecular assembling on glycoclusters, giving mechanistic insights into physiological and pathological molecular events on cell surfaces as well as clues for the design and creation of molecular systems exerting improved glycofunctions. Further development and accumulation of such studies will allow detailed understanding and artificial control of the "glycosynapse" foreseen by Dr. Sen-itiroh Hakomori.

Comprehensive characterization of oligosaccharide conformational ensembles with conformer classification by free-energy landscape via reproductive kernel Hilbert space.

Oligosaccharides play versatile roles in various biological systems but are difficult to characterize from a structural viewpoint due to their remarkable degrees of freedom in internal motion. Therefore, molecular dynamics simulations have been widely used to delineate the dynamic conformations of oligosaccharides. However, hardly any methods have thus far been available for the comprehensive characterization of simulation-derived conformational ensembles of oligosaccharides. In this research, we attempted to develop a non-linear multivariate analysis by employing a kernel method using two homologous high-mannose-type oligosaccharides composed of ten and eleven residues as model molecules. These oligosaccharides' conformers derived from simulations were mapped into reproductive kernel Hilbert space with a positive definite function in which all required non-redundant variables for describing the oligosaccharide conformations can be treated in a non-biased manner. By applying Gaussian mixture model clustering, the oligosaccharide conformers were successfully classified by different funnels in the free-energy landscape, enabling a systematic comparison of conformational ensembles of the homologous oligosaccharides. The results shed light on the contributions of intraresidue conformational factors such as the hydroxyl group orientation and/or ring puckering state to their global conformational dynamics. Our methodology will open opportunities to explore oligosaccharides' conformational spaces, and more generally, molecules with high degrees of motional freedom.

Risk perception regarding implementation of iodine thyroid blocking during a nuclear disaster of mothers living near a nuclear power station in Japan.

Pre-emptive evacuation orders following the accident at the Fukushima Daiichi Nuclear Power Station (FDNPS) in March 2011 and subsequent regulatory limits regarding contaminated food, milk, and water minimized the external and internal radiation exposure doses of nearby residents. However, with regard to implementation of iodine thyroid blocking (ITB), residents were confused because no information on the matter was released by the central and/or local governments. Based on lessons learned from the FDNPS accident, many countries have revised their guidelines regarding ITB during nuclear disasters. To adequately revise such guidelines and ensure effective ITB implementation during a nuclear disaster, however, residents' perceptions of ITB must be clarified. In this study, the perception of risks associated with ITB was investigated in mothers residing near the Sendai Nuclear Power Plant (SNPP) in Kagoshima Prefecture, Japan. Of the 520 mothers surveyed, 467 (89.8%) expressed anxiety regarding the administration of potassium iodine (KI) to their children. Logistic regression analysis revealed that the mothers' anxiety regarding the administration of KI to their children was positively correlated with their wish to consult an expert about KI and their hesitation to let their children eat foods produced in Fukushima, and negatively correlated with having confidence about administering KI to their children. Careful communication of potential risks to mothers residing near nuclear power plants is thus critical for implementing effective ITB in children.

Ribitol in Solution Is an Equilibrium of Asymmetric Conformations.

Ribitol (C5H12O5), an acyclic sugar alcohol, is present on mammalian α-dystroglycan as a component of O-mannose glycan. In this study, we examine the conformation and dynamics of ribitol by database analysis, experiments, and computational methods. Database analysis reveals that the anti-conformation (180°) is populated at the C3-C4 dihedral angle, while the gauche conformation (±60°) is seen at the C2-C3 dihedral angle. Such conformational asymmetry was born out in a solid-state 13C-NMR spectrum of crystalline ribitol, where C1 and C5 signals are unequal. On the other hand, solution 13C-NMR has identical chemical shifts for C1 and C5. NMR 3J coupling constants and OH exchange rates suggest that ribitol is an equilibrium of conformations, under the influence of hydrogen bonds and/or steric hinderance. Molecular dynamics (MD) simulations allowed us to discuss such a chemically symmetric molecule, pinpointing the presence of asymmetric conformations evidenced by the presence of correlations between C2-C3 and C3-C4 dihedral angles. These findings provide a basis for understanding the dynamic structure of ribitol and the function of ribitol-binding enzymes.

Remodeling of the Oligosaccharide Conformational Space in the Prebound State To Improve Lectin-Binding Affinity.

We developed an approach to improve the lectin-binding affinity of an oligosaccharide by remodeling its conformational space in the precomplexed state. To develop this approach, we used a Lewis X-containing oligosaccharide interacting with RSL as a model system. Using an experimentally validated molecular dynamics simulation, we designed a Lewis X analogue with an increased population of conformational species that were originally very minor but exclusively accessible to the target lectin without steric hindrance by modifying the nonreducing terminal galactose, which does not directly contact the lectin in the complex. This Lewis X mimetic showed 17 times higher affinity for the lectin than the native counterpart. Our approach, complementing the lectin-bound-state optimizations, offers an alternative strategy to create high-affinity oligosaccharides by increasing populations of on-pathway metastable conformers.

Field-stepwise-swept QCPMG solid-state 115In NMR of indium oxide.

Experimental and theoretical investigations of indium-115 electric-field-gradient (EFG) tensors of indium(III) oxide, In2O3, have been presented. Field-stepwise-swept QCPMG solid-state 115In NMR experiments are carried out at T â€‹= â€‹120 â€‹K, observed at 52.695 â€‹MHz, and in the range of external magnetic fields between 4.0 and 6.5 â€‹T. The spectral simulations yield the quadrupolar coupling constant, CQ value, of 183(2) MHz and the asymmetry parameter, ηQ, of 0.05(5), for In(1), and that of 126(2) MHz and ηQ of 0.86(5) for In(2). Quantum chemical calculations are carried out to provide 115In EFG tensor orientations with respect to the molecular structure. A relationship between operative frequencies and variable ranges of external magnetic fields is briefly discussed for field-swept solid-state 115In NMR.

Effect of the Cationic Head Group on Cationic Surfactant-Based Surfactant Mediated Gelation (SMG).

The surfactant-mediated gelation (SMG) method allows us to formulate hydrogels using a water-insoluble organogelator. In this study, we formulated hydrogels using three cationic surfactants, hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride (CTAC), and hexadecylpyridinium chloride (CPC)] and an organogelator (12-hydroxyoctadecanoic acid (12-HOA), and studied their structures and mechanical properties. A fiber-like structure similar to that found in the 12-HOA-based organogels was observed by optical microscopy. Small- and wide-angle X-ray scattering profiles showed Bragg peaks derived from the long- and short-spacing of the crystalline structures in the gel fibers and a correlation peak from the surfactant micelles in the small-angle region. Furthermore, the formation of micelles in the hydrogels was confirmed by UV-vis spectroscopic measurements of the gel samples in the presence of Rhodamine 6G. We concluded that the hydrogels prepared by the SMG method in the present systems are orthogonal molecular assembled systems in which two different molecular assembled structures coexist. Among the three surfactant systems, the CTAB system presented the lowest critical gelation concentration and highest sol-gel transition temperature and viscoelasticity. These differences in gel fiber formation and gel properties were discussed from the viewpoint of the degree of solubilization of the gelator molecules in micelles coexisting with gel fibers and diffusion of the gelator molecules in the gel formation process.

(R)-Ketamine Induces a Greater Increase in Prefrontal 5-HT Release Than (S)-Ketamine and Ketamine Metabolites via an AMPA Receptor-Independent Mechanism.

BACKGROUND: Although recent studies provide insight into the molecular mechanisms of the effects of ketamine, the antidepressant mechanism of ketamine enantiomers and their metabolites is not fully understood. In view of the involvement of mechanisms other than the N-methyl-D-aspartate receptor in ketamine's action, we investigated the effects of (R)-ketamine, (S)-ketamine, (R)-norketamine [(R)-NK], (S)-NK, (2R,6R)-hydroxynorketamine [(2R,6R)-HNK], and (2S,6S)-HNK on monoaminergic neurotransmission in the prefrontal cortex of mice. METHODS: The extracellular monoamine levels in the prefrontal cortex were measured by in vivo microdialysis. RESULTS: (R)-Ketamine and (S)-ketamine acutely increased serotonin release in a dose-dependent manner, and the effect of (R)-ketamine was greater than that of (S)-ketamine. In contrast, (S)-ketamine caused a robust increase in dopamine release compared with (R)-ketamine. Both ketamine enantiomers increased noradrenaline release, but these effects did not differ. (2R,6R)-HNK caused a slight but significant increase in serotonin and noradrenaline but not dopamine release. (S)-NK increased dopamine and noradrenaline but not serotonin release. Differential effects between (R)-ketamine and (S)-ketamine were also observed in a lipopolysaccharide-induced model of depression. An α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4- tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX), attenuated (S)-ketamine-induced, but not (R)-ketamine-induced serotonin release, whereas NBQX blocked dopamine release induced by both enantiomers. Local application of (R)-ketamine into the prefrontal cortex caused a greater increase in prefrontal serotonin release than that of (S)-ketamine. CONCLUSIONS: (R)-Ketamine strongly activates the prefrontal serotonergic system through an AMPA receptor-independent mechanism. (S)-Ketamine-induced serotonin and dopamine release was AMPA receptor-dependent. These findings provide a neurochemical basis for the underlying pharmacological differences between ketamine enantiomers and their metabolites.

[Successful Use of Percutaneous Left Ventricular Assist Device( Impella) and Veno Artery Extracorporeal Membrane Oxygenation( VA-ECMO) for Ischemic Cardiogenic Shock;Report of a Case].

A 73-year-old male was referred to our hospital for acute congestive heart failure. His cardiac and respiratory conditions were worsening with cardiogenic shock requiring intubation. Coronary angiography revealed severe triple vessel disease, and echocardiography showed severe left ventricular dysfunction. Therefore, he underwent veno artery extracorporeal membrane oxygenation (VA-ECMO) followed by percutaneous left ventricular assist device (Impella). His cardiac condition improved and VA-ECMO and Impella were removed on the 2nd day and the 4th day after surgery, respectively. He underwent off-pump coronary artery bypass grafting (OPCAB) without any complication on the 36th day. Postoperative course was uneventful and he was discharged on postoperative day 30. Concomitant use of Impella and VA-ECMO (Ecpella) remarkably improved ischemic cardiogenic shock by unloading the left ventricle and increasing the cardiac output.

Lewis X-Carrying Neoglycolipids Evoke Selective Apoptosis in Neural Stem Cells.

N-glycans carrying the Lewis X trisaccharide [Galß1-4 (Fucα1-3) GlcNAc] are expressed by neural stem cells (NSCs) exclusively before differentiation, and they actively contribute to the maintenance of stemness of these cells. To address the functional roles of the Lewis X-mediated molecular interactions in NSCs, we created a series of synthetic neoglycolipids that contained a Lewis X-carrying glycan connected to an acyl chain through an amide bond. The neoglycolipids formed aqueous micelles displaying functional Lewis X glycotopes. Surprisingly, the neoglycolipid micelles evoked selective apoptosis in undifferentiated NSCs, whereas their differentiated cells remained unaffected. The apoptotic activity depended on the structural integrity of the Lewis X glycotopes and also on the length of the acyl chain, with an optimum length of C18. We propose hypothetical functional mechanisms of the neoglycolipid, which involves selective NSC targeting with Lewis X glycan and apoptotic signaling by the intracellular release of fatty acids. This serendipitous finding may offer a new strategy for controlling neural cell fates using artificial glycoclusters.

Synthetic Approach to biomolecular science by cyborg supramolecular chemistry.

BACKGROUND: To imitate the essence of living systems via synthetic chemistry approaches has been attempted. With the progress in supramolecular chemistry, it has become possible to synthesize molecules of a size and complexity close to those of biomacromolecules. Recently, the combination of precisely designed supramolecules with biomolecules has generated structural platforms for designing and creating unique molecular systems. Bridging between synthetic chemistry and biomolecular science is also developing methodologies for the creation of artificial cellular systems. SCOPE OF REVIEW: This paper provides an overview of the recently expanding interdisciplinary research to fuse artificial molecules with biomolecules, that can deepen our understanding of the dynamical ordering of biomolecules. MAJOR CONCLUSIONS AND GENERAL SIGNIFICANCE: Using bottom-up approaches based on the precise chemical design, synthesis and hybridization of artificial molecules with biological materials have been realizing the construction of sophisticated platforms having the fundamental functions of living systems. The effective hybrid, molecular cyborg, approaches enable not only the establishment of dynamic systems mimicking nature and thus well-defined models for biophysical understanding, but also the creation of those with highly advanced, integrated functions. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.

Conformational Analysis of a High-Mannose-Type Oligosaccharide Displaying Glucosyl Determinant Recognised by Molecular Chaperones Using NMR-Validated Molecular Dynamics Simulation.

Exploration of the conformational spaces of flexible oligosaccharides is essential to gain deeper insights into their functional mechanisms. Here we characterised dynamic conformation of a high-mannose-type dodecasaccharide with a terminal glucose residue, a critical determinant recognised by molecular chaperones. The dodecasaccharide was prepared by our developed chemoenzymatic technique, which uses 13 C labelling and lanthanide tagging to detect conformation-dependent paramagnetic effects by NMR spectroscopy. The NMR-validated molecular dynamics simulation produced the dynamic conformational ensemble of the dodecasaccharide. This determined its spatial distribution as well as the glycosidic linkage conformation of the terminal glucose determinant. Moreover, comparison of our results with previously reported crystallographic data indicates that the chaperone binding to its target oligosaccharides involves an induced-fit mechanism.

Stable isotope labeling of glycoprotein expressed in silkworms using immunoglobulin G as a test molecule.

Silkworms serve as promising bioreactors for the production of recombinant proteins, including glycoproteins and membrane proteins, for structural and functional protein analyses. However, lack of methodology for stable isotope labeling has been a major deterrent to using this expression system for nuclear magnetic resonance (NMR) structural biology. Here we developed a metabolic isotope labeling technique using commercially available silkworm larvae. The fifth instar larvae were infected with baculoviruses for co-expression of recombinant human immunoglobulin G (IgG) as a test molecule, with calnexin as a chaperone. They were subsequently reared on an artificial diet containing (15)N-labeled yeast crude protein extract. We harvested 0.1 mg of IgG from larva with a (15)N-enrichment ratio of approximately 80%. This allowed us to compare NMR spectral data of the Fc fragment cleaved from the silkworm-produced IgG with those of an authentic Fc glycoprotein derived from mammalian cells. Therefore, we successfully demonstrated that our method enables production of isotopically labeled glycoproteins for NMR studies.

Paramagnetic NMR probes for characterization of the dynamic conformations and interactions of oligosaccharides.

Paramagnetism-assisted nuclear magnetic resonance (NMR) techniques have recently been applied to a wide variety of biomolecular systems, using sophisticated immobilization methods to attach paramagnetic probes, such as spin labels and lanthanide-chelating groups, at specific sites of the target biomolecules. This is also true in the field of carbohydrate NMR spectroscopy. NMR analysis of oligosaccharides is often precluded by peak overlap resulting from the lack of variability of local chemical structures, by the insufficiency of conformational restraints from nuclear Overhauser effect (NOE) data due to low proton density, and moreover, by the inherently flexible nature of carbohydrate chains. Paramagnetic probes attached to the reducing ends of oligosaccharides cause paramagnetic relaxation enhancements (PREs) and/or pseudocontact shifts (PCSs) resolve the peak overlap problem. These spectral perturbations can be sources of long-range atomic distance information, which complements the local conformational information derived from J couplings and NOEs. Furthermore, paramagnetic NMR approaches, in conjunction with computational methods, have opened up possibilities for the description of dynamic conformational ensembles of oligosaccharides in solution. Several applications of paramagnetic NMR techniques are presented to demonstrate their utility for characterizing the conformational dynamics of oligosaccharides and for probing the carbohydrate-recognition modes of proteins. These techniques can be applied to the characterization of transient, non-stoichiometric interactions and will contribute to the visualization of dynamic biomolecular processes involving sugar chains.

NMR-based structural validation of therapeutic antibody produced in Nicotiana benthamiana.

KEY MESSAGE: We successfully developed a method for metabolic isotope labeling of recombinant proteins produced in transgenic tobacco. This enabled assessment of structural integrity of plant-derived therapeutic antibodies by NMR analysis. A variety of expression vehicles have been developed for the production of promising biologics, including plants, fungi, bacteria, insects, and mammals. Glycoprotein biologics often experience altered folding and post-translational modifications that are typified by variant glycosylation patterns. These differences can dramatically affect their efficacy, as exemplified by therapeutic antibodies. However, it is generally difficult to validate the structural integrity of biologics produced using different expression vehicles. To address this issue, we have developed and applied a stable-isotope-assisted nuclear magnetic resonance (NMR) spectroscopy method for the conformational characterization of recombinant antibodies produced in plants. Nicotiana benthamiana used as a vehicle for the production of recombinant immunoglobulin G (IgG) was grown in a (15)N-enriched plant growth medium. The Fc fragment derived from the (15)N-labeled antibody thus prepared was subjected to heteronuclear two-dimensional (2D) NMR measurements. This approach enabled assessment of the structural integrity of the plant-derived therapeutic antibodies by comparing their NMR spectral properties with those of an authentic IgG-Fc derived from mammalian cells.

Emerging structural insights into glycoprotein quality control coupled with N-glycan processing in the endoplasmic reticulum.

In the endoplasmic reticulum (ER), the sugar chain is initially introduced onto newly synthesized proteins as a triantennary tetradecasaccharide (Glc3Man9GlcNAc2). The attached oligosaccharide chain is subjected to stepwise trimming by the actions of specific glucosidases and mannosidases. In these processes, the transiently expressed N-glycans, as processing intermediates, function as signals for the determination of glycoprotein fates, i.e., folding, transport, or degradation through interactions of a series of intracellular lectins. The monoglucosylated glycoforms are hallmarks of incompletely folded states of glycoproteins in this system, whereas the outer mannose trimming leads to ER-associated glycoprotein degradation. This review outlines the recently emerging evidence regarding the molecular and structural basis of this glycoprotein quality control system, which is regulated through dynamic interplay among intracellular lectins, glycosidases, and glycosyltransferase. Structural snapshots of carbohydrate-lectin interactions have been provided at the atomic level using X-ray crystallographic analyses. Conformational ensembles of uncomplexed triantennary high-mannose-type oligosaccharides have been characterized in a quantitative manner using molecular dynamics simulation in conjunction with nuclear magnetic resonance spectroscopy. These complementary views provide new insights into glycoprotein recognition in quality control coupled with N-glycan processing.

A Self-Assembled Spherical Complex Displaying a Gangliosidic Glycan Cluster Capable of Interacting with Amyloidogenic Proteins.

Physiological and pathological functions of glycans are promoted through their clustering effects as exemplified by a series of gangliosides, sialylated glycosphingolipids, which serve as acceptors for bacterial toxins and viruses. Furthermore, ganglioside GM1 clusters on neuronal cell membranes specifically interact with amyloidogenic proteins, triggering their conformational transitions and leading to neurodegeneration. Here we develop a self-assembled spherical complex that displays a cluster of the GM1 pentasaccharide, and successfully demonstrate its ability to interact with amyloidâ€…ß and α-synuclein. Due to the lack of hydrophobic lipid moieties, which would stably trap these cohesive proteins or give rise to toxic aggregates, this artificial cluster enabled NMR spectroscopic characterization of the early encounter stage of protein interactions with its outer carbohydrate moieties, which were not observable with previous glycan clusters.