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Carbohydrate Polymers Oct 2024Bacterial pathogens can cause a broad range of infections with detrimental effects on health. Vaccine development is essential as multi-drug resistance in bacterial...
Bacterial pathogens can cause a broad range of infections with detrimental effects on health. Vaccine development is essential as multi-drug resistance in bacterial infections is a rising concern. Recombinantly produced proteins carrying O-antigen glycosylation are promising glycoconjugate vaccine candidates to prevent bacterial infections. However, methods for their comprehensive structural characterization are lacking. Here, we present a bottom-up approach for their site-specific characterization, detecting N-glycopeptides by nano reversed-phase liquid chromatography-mass spectrometry (RP-LC-MS). Glycopeptide analyses revealed information on partial site-occupancy and site-specific glycosylation heterogeneity and helped corroborate the polysaccharide structures and their modifications. Bottom-up analysis was complemented by intact glycoprotein analysis using nano RP-LC-MS allowing the fast visualization of the polysaccharide distribution in the intact glycoconjugate. At the glycopeptide level, the model glycoconjugates analyzed showed different repeat unit (RU) distributions that spanned from 1 to 21 RUs attached to each of the different glycosylation sites. Interestingly, the intact glycoprotein analysis displayed a RU distribution ranging from 1 to 28 RUs, showing the predominant species when the different glycopeptide distributions are combined in the intact glycoconjugate. The complete workflow based on LC-MS measurements allows detailed and comprehensive analysis of the glycosylation state of glycoconjugate vaccines.
Topics: Glycoconjugates; Bacterial Vaccines; Glycosylation; Glycopeptides; Mass Spectrometry; Vaccines, Conjugate; Chromatography, Liquid; Chromatography, Reverse-Phase
PubMed: 38876725
DOI: 10.1016/j.carbpol.2024.122327 -
Frontiers in Pharmacology 2024Visceral Leishmaniasis (VL) is a serious public health issue, documented in more than ninety countries, where an estimated 500,000 new cases emerge each year. Regardless...
Visceral Leishmaniasis (VL) is a serious public health issue, documented in more than ninety countries, where an estimated 500,000 new cases emerge each year. Regardless of novel methodologies, advancements, and experimental interventions, therapeutic limitations, and drug resistance are still challenging. For this reason, based on previous research, we screened natural products (NP) from Nuclei of Bioassays, Ecophysiology, and Biosynthesis of Natural Products Database (NuBBE, Mexican Compound Database of Natural Products (BIOFACQUIM), and Peruvian Natural Products Database (PeruNPDB) databases, in addition to structural analogs of Miglitol and Acarbose, which have been suggested as treatments for VL and have shown encouraging action against parasite's N-glycan biosynthesis. Using computer-aided drug design (CADD) approaches, the potential inhibitory effect of these NP candidates was evaluated by inhibiting the Mannosyl-oligosaccharide Glucosidase Protein (MOGS) from , an enzyme essential for the protein glycosylation process, at various pH to mimic the parasite's changing environment. Also, computational analysis was used to evaluate the Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) profile, while molecular dynamic simulations were used to gather information on the interactions between these ligands and the protein target. Our findings indicated that Ocotillone and Subsessiline have potential antileishmanial effects at pH 5 and 7, respectively, due to their high binding affinity to MOGS and interactions in the active center. Furthermore, these compounds were non-toxic and had the potential to be administered orally. This research indicates the promising anti-leishmanial activity of Ocotillone and Subsessiline, suggesting further validation through and experiments.
PubMed: 38873424
DOI: 10.3389/fphar.2024.1403203 -
Chemical Science Jun 2024Protein-protein interactions of c-Myc (MYC) are often regulated by post-translational modifications (PTMs), such as phosphorylation, and crosstalk thereof. Studying...
Protein-protein interactions of c-Myc (MYC) are often regulated by post-translational modifications (PTMs), such as phosphorylation, and crosstalk thereof. Studying these interactions requires proteins with unique PTM patterns, which are challenging to obtain by recombinant methods. Standard peptide synthesis and native chemical ligation can produce such modified proteins, but are time-consuming and therefore typically limited to the study of individual PTMs. Herein, we report the development of flow-based methods for the rapid synthesis of phosphorylated MYC sequences (up to 84 AA), and demonstrate the versatility of this approach for the incorporation of other PTMs ( -methylation, sulfation, acetylation, glycosylation) and combinations thereof. Peptides containing up to seven PTMs and phosphorylation at up to five sites were successfully prepared and isolated in high yield and purity. We further produced ten PTM-decorated analogues of the MYC Transactivation Domain (TAD) to screen for binding to the tumor suppressor protein, Bin1, using heteronuclear NMR and native mass spectrometry. We determined the effects of phosphorylation and glycosylation on the strength of the MYC:Bin1 interaction, and reveal an influence of MYC sequence length on binding. Our platform for the rapid synthesis of MYC sequences up to 84 AA with distinct PTM patterns thus enables the systematic study of PTM function at a molecular level, and offers a convenient way for expedited screening of constructs.
PubMed: 38873065
DOI: 10.1039/d4sc00481g -
Frontiers in Oral Health 2024, a member of the "red complex" bacteria implicated in severe periodontitis, employs various survival strategies and virulence factors to interact with the host. It...
, a member of the "red complex" bacteria implicated in severe periodontitis, employs various survival strategies and virulence factors to interact with the host. It thrives as a late colonizer in the oral biofilm, relying on its unique adaptation mechanisms for persistence. Essential to its survival are the type 9 protein secretion system and -glycosylation of proteins, crucial for host interaction and immune evasion. Virulence factors of , including sialidase and proteases, facilitate its pathogenicity by degrading host glycoproteins and proteins, respectively. Moreover, cell surface glycoproteins like the S-layer and BspA modulate host responses and bacterial adherence, influencing colonization and tissue invasion. Outer membrane vesicles and lipopolysaccharides further induce inflammatory responses, contributing to periodontal tissue destruction. Interactions with specific host cell types, including epithelial cells, polymorphonuclear leukocytes macrophages, and mesenchymal stromal cells, highlight the multifaceted nature of pathogenicity. Notably, it can invade epithelial cells and impair PMN function, promoting dysregulated inflammation and bacterial survival. Comparative studies with periodontitis-associated reveal differences in protease activity and immune modulation, suggesting distinct roles in disease progression. potential to influence oral antimicrobial defense through protease-mediated degradation and interactions with other bacteria underscores its significance in periodontal disease pathogenesis. However, understanding precise role in host-microbiome interactions and its classification as a keystone pathogen requires further investigation. Challenges in translating research data stem from the complexity of the oral microbiome and biofilm dynamics, necessitating comprehensive studies to elucidate its clinical relevance and therapeutic implications in periodontitis management.
PubMed: 38872984
DOI: 10.3389/froh.2024.1434217 -
Frontiers in Veterinary Science 2024-glycosylation is a highly conserved glycan modification that plays crucial roles in various physiological processes, including protein folding, trafficking, and signal...
-glycosylation is a highly conserved glycan modification that plays crucial roles in various physiological processes, including protein folding, trafficking, and signal transduction. Porcine deltacoronavirus (PDCoV) poses a newly emerging threat to the global porcine industry. The spike protein of PDCoV exhibits a high level of -glycosylation; however, its role in viral infection remains poorly understood. In this study, we applied a lentivirus-based entry reporter system to investigate the role of -glycosylation on the viral spike protein during PDCoV entry stage. Our findings demonstrate that -glycosylation at positions 652 and 661 of the viral spike protein significantly reduces the infectivity of PDCoV pseudotyped virus. Overall, our results unveil a novel function of -glycosylation in PDCoV infection, highlighting its potential for facilitating the development of antiviral strategies.
PubMed: 38872801
DOI: 10.3389/fvets.2024.1430113 -
Cell Jun 2024
PubMed: 38870945
DOI: 10.1016/j.cell.2024.06.004 -
Synthetic and Systems Biotechnology Dec 2024Digitoxose, a significant 2,6-dideoxyhexose found in nature, exists in many small-molecule natural products. These digitoxose-containing natural products can be divided... (Review)
Review
Digitoxose, a significant 2,6-dideoxyhexose found in nature, exists in many small-molecule natural products. These digitoxose-containing natural products can be divided into steroids, macrolides, macrolactams, anthracyclines, quinones, enediynes, acyclic polyene, indoles and oligosaccharides, that exhibit antibacterial, anti-viral, antiarrhythmic, and antitumor activities respectively. As most of digitoxose-containing natural products for clinical application or preclinical tests, this review also summarizes the biosynthesis of digitoxose, and application of compound diversification by introducing sugar plasmids. It may provide a practical approach to expanding the diversity of digitoxose-containing products.
PubMed: 38868608
DOI: 10.1016/j.synbio.2024.05.012 -
AMB Express Jun 2024High throughput screening (HTS) methods of enzyme variants are essential for the development of robust biocatalysts suited for low impact, industrial scale, biobased...
High throughput screening (HTS) methods of enzyme variants are essential for the development of robust biocatalysts suited for low impact, industrial scale, biobased synthesis of a myriad of compounds. However, for the majority of enzyme classes, current screening methods have limited throughput, or need expensive substrates in combination with sophisticated setups. Here, we present a straightforward, high throughput selection system that couples sucrose synthase activity to growth. Enabling high throughput screening of this enzyme class holds the potential to facilitate the creation of robust variants, which in turn can significantly impact the future of cost effective industrial glycosylation.
PubMed: 38865019
DOI: 10.1186/s13568-024-01727-y -
ELife Jun 2024Glycosylation of the SARS-CoV-2 spike (S) protein represents a key target for viral evolution because it affects both viral evasion and fitness. Successful variations in...
Glycosylation of the SARS-CoV-2 spike (S) protein represents a key target for viral evolution because it affects both viral evasion and fitness. Successful variations in the glycan shield are difficult to achieve though, as protein glycosylation is also critical to folding and structural stability. Within this framework, the identification of glycosylation sites that are structurally dispensable can provide insight into the evolutionary mechanisms of the shield and inform immune surveillance. In this work, we show through over 45 μs of cumulative sampling from conventional and enhanced molecular dynamics (MD) simulations, how the structure of the immunodominant S receptor binding domain (RBD) is regulated by -glycosylation at N343 and how this glycan's structural role changes from WHu-1, alpha (B.1.1.7), and beta (B.1.351), to the delta (B.1.617.2), and omicron (BA.1 and BA.2.86) variants. More specifically, we find that the amphipathic nature of the -glycan is instrumental to preserve the structural integrity of the RBD hydrophobic core and that loss of glycosylation at N343 triggers a specific and consistent conformational change. We show how this change allosterically regulates the conformation of the receptor binding motif (RBM) in the WHu-1, alpha, and beta RBDs, but not in the delta and omicron variants, due to mutations that reinforce the RBD architecture. In support of these findings, we show that the binding of the RBD to monosialylated ganglioside co-receptors is highly dependent on N343 glycosylation in the WHu-1, but not in the delta RBD, and that affinity changes significantly across VoCs. Ultimately, the molecular and functional insight we provide in this work reinforces our understanding of the role of glycosylation in protein structure and function and it also allows us to identify the structural constraints within which the glycosylation site at N343 can become a hotspot for mutations in the SARS-CoV-2 S glycan shield.
Topics: Glycosylation; Spike Glycoprotein, Coronavirus; SARS-CoV-2; Humans; Molecular Dynamics Simulation; Protein Binding; COVID-19; Polysaccharides; Protein Domains; Binding Sites; Protein Conformation; Mutation
PubMed: 38864493
DOI: 10.7554/eLife.95708 -
Horticulture Research Jun 2024Citrus fruits have abundant flavonoid glycosides (FGs), an important class of natural functional and flavor components. However, there have been few reports about the...
Citrus fruits have abundant flavonoid glycosides (FGs), an important class of natural functional and flavor components. However, there have been few reports about the modification of UDP-glycosyltransferases (UGTs) on flavonoids in citrus. Notably, in flavonoid biosynthesis, 7--glucosylation is the initial and essential step of glycosylation prior to the synthesis of flavanone disaccharides, the most abundant and iconic FGs in citrus fruits. Here, based on the accumulation of FGs observed at the very early fruit development stage of two pummelo varieties, we screened six novel flavonoid 7--glucosyltransferase genes () transcriptomic analysis and then characterized them . The results revealed that four Cg7GlcTs possess wide catalytic activities towards various flavonoid substrates, with CgUGT89AK1 exhibiting the highest catalytic efficiency. Transient overexpression of and led to increases in FG synthesis in pummelo leaves. Interestingly, these two genes had conserved sequences and consistent functions across different germplasms. Moreover, was found to play a role in the response of citrus to Huanglongbing infection by promoting FG production. The findings improve our understanding of flavonoid 7--glucosylation by identifying the key genes, and may help improve the benefits of flavonoid biosynthesis for plants and humans in the future.
PubMed: 38863995
DOI: 10.1093/hr/uhae098