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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 -
Biology Letters Jun 2024Glycation reactions play a key role in the senescence process and are involved in numerous age-related pathologies, such as diabetes complications or Alzheimer's... (Review)
Review
Glycation reactions play a key role in the senescence process and are involved in numerous age-related pathologies, such as diabetes complications or Alzheimer's disease. As a result, past studies on glycation have mostly focused on human and laboratory animal models for medical purposes. Very little is known about glycation and its link to senescence in wild animal species. Yet, despite feeding on high-sugar diets, several bat and bird species are long-lived and seem to escape the toxic effects of high glycaemia. The study of these models could open new avenues both for understanding the mechanisms that coevolved with glycation resistance and for treating the damaging effects of glycations in humans. Our understanding of glycaemia's correlation to proxies of animals' pace of life is emerging in few wild species; however, virtually nothing is known about their resistance to glycation, nor on the relationship between glycation, species' life-history traits and individual fitness. Our review summarizes the scarce current knowledge on the links between glycation and life-history traits in non-conventional animal models, highlighting the predominance of avian research. We also investigate some key molecular and physiological parameters involved in glycation regulation, which hold promise for future research on fitness and senescence of individuals.
Topics: Animals; Life History Traits; Birds; Models, Animal; Glycosylation; Aging; Glycation End Products, Advanced
PubMed: 38863347
DOI: 10.1098/rsbl.2023.0601 -
Microbiology Resource Announcements Jun 2024, a member of the family and species , is an F1 cluster phage that infects mc²155. The Maravista genome has 61.3% GC content, is 60,140 bp in length, and encodes 104...
, a member of the family and species , is an F1 cluster phage that infects mc²155. The Maravista genome has 61.3% GC content, is 60,140 bp in length, and encodes 104 putative genes. Maravista encodes two putative glycosyltransferases, suggesting glycosylation of its capsid protein.
PubMed: 38860805
DOI: 10.1128/mra.00502-24 -
American Journal of Cancer Research 2024Chemotherapy is the principal treatment for advanced cancer patients. However, chemotherapeutic resistance, an important hallmark of cancer, is considered as a key... (Review)
Review
Chemotherapy is the principal treatment for advanced cancer patients. However, chemotherapeutic resistance, an important hallmark of cancer, is considered as a key impediment to effective therapy in cancer patients. Multiple signaling pathways and factors have been underscored to participate in governing drug resistance. Posttranslational modifications, including ubiquitination, glycosylation, acetylation and phosphorylation, have emerged as key players in modulating drug resistance in gynecological tumors, such as ovarian cancer, cervical cancer and endometrial cancer. In this review article, we summarize the role of ubiquitination in governing drug sensitivity in gynecological cancers. Moreover, we describe the numerous compounds that target ubiquitination in gynecological cancers to reverse chemotherapeutic resistance. In addition, we provide the future perspectives to fully elucidate the mechanisms by which ubiquitination controls drug resistance in gynecological tumors, contributing to restoring drug sensitivity. This review highlights the complex interplay between ubiquitination and drug resistance in gynecological tumors, providing novel insights into potential therapeutic targets and personalized treatment strategies to overcome the bottleneck of drug resistance.
PubMed: 38859858
DOI: 10.62347/WYKZ9784 -
American Journal of Cancer Research 2024Whether serum Mac-2 binding protein glycosylation isomer (M2BPGi) level at year 5 of treatment could predict hepatocellular carcinoma (HCC) development and mortality...
Mac-2 binding protein glycosylation isomer at 5 years of antiviral therapy predict hepatocellular carcinoma and mortality beyond year 5 in chronic hepatitis B patients with cirrhosis.
Whether serum Mac-2 binding protein glycosylation isomer (M2BPGi) level at year 5 of treatment could predict hepatocellular carcinoma (HCC) development and mortality beyond year 5 of entecavir or tenofovir disoproxil fumarate (TDF) treatment in chronic hepatitis B (CHB) patients with cirrhosis remain unclear. This retrospective study investigated the role of M2BPGi level at year 5 of treatment in predicting HCC and mortality beyond year 5 in CHB patients with cirrhosis. This study analyzed 1385 cirrhotic patients receiving entecavir or TDF treatment. Of them, 899 patients who did not develop HCC within the first 5 years of treatment were enrolled. In the entire cohort, there was no significant difference in the annual incidence of HCC before and after year 5 of entecavir or TDF treatment ( = 0.455). Multivariable Cox analysis identified old age, higher AFP and M2BPGi levels at 5 years of treatment as independent predictors of HCC occurrence beyond year 5. We developed the HCC risk prediction model, AMA, based on age, M2BPGi and AFP levels at 5 years of treatment, with the total score ranging from 0 to 8. The AMA model accurately categorized patients into low (≤2), medium (2-5), and high (≥5) risk groups in the development and validation groups (<0.001) and exhibited good discriminant function in predicting HCC beyond year 5 in cirrhotic patients (AUROC: 0.743 at 5 years). The M2BPGi of 1.0 COI at 5 years of treatment stratified the risk of all-cause and liver-related mortality beyond year 5 (<0.001). In conclusions, M2BPGi level at 5 years of treatment is a useful marker for predicting HCC development and mortality beyond year 5 of entecavir or TDF therapy in CHB patients with cirrhosis.
PubMed: 38859836
DOI: 10.62347/DAGB7277 -
Microbial Biotechnology Jun 2024The application of bacterial oligosaccharyltransferases (OSTs) such as the Campylobacter jejuni PglB for glycoengineering has attracted considerable interest in...
The application of bacterial oligosaccharyltransferases (OSTs) such as the Campylobacter jejuni PglB for glycoengineering has attracted considerable interest in glycoengineering and glycoconjugate vaccine development. However, PglB has limited specificity for glycans that can be transferred to candidate proteins, which along with other factors is dependent on the reducing end sugar of glycans. In this study, we developed a cell-free glycosylation assay that offers the speed and simplicity of a 'yes' or 'no' determination. Using the assay, we tested the activity of eleven PglBs from Campylobacter species and more distantly related bacteria. The following assorted glycans with diverse reducing end sugars were tested for transfer, including Streptococcus pneumoniae capsule serotype 4, Salmonella enterica serovar Typhimurium O antigen (B1), Francisella tularensis O antigen, Escherichia coli O9 antigen and Campylobacter jejuni heptasaccharide. Interestingly, while PglBs from the same genus showed high activity, whereas divergent PglBs differed in their transfer of glycans to an acceptor protein. Notably for glycoengineering purposes, Campylobacter hepaticus and Campylobacter subantarcticus PglBs showed high glycosylation efficiency, with C. hepaticus PglB potentially being useful for glycoconjugate vaccine production. This study demonstrates the versatility of the cell-free assay in rapidly assessing an OST to couple glycan/carrier protein combinations and lays the foundation for future screening of PglBs by linking amino acid similarity to glycosyltransferase activity.
Topics: Hexosyltransferases; Glycosylation; Membrane Proteins; Campylobacter; Polysaccharides; Cell-Free System; Campylobacter jejuni; Bacterial Proteins; Glycoconjugates
PubMed: 38858807
DOI: 10.1111/1751-7915.14480 -
Iranian Journal of Microbiology Apr 2024The influenza A(H1N1) virus is known for large outbreaks, epidemics and pandemics worldwide owing to its genome plasticity which evolves constantly. In the year 2015 and...
BACKGROUND AND OBJECTIVES
The influenza A(H1N1) virus is known for large outbreaks, epidemics and pandemics worldwide owing to its genome plasticity which evolves constantly. In the year 2015 and then in 2017, India witnessed an upsurge in cases.
MATERIALS AND METHODS
The study was carried out in this period (2015-2017) with samples from 5 states across north India. The hemagglutinin 1 (HA1) and non-structural 1 (NS1) gene segments of the viral genome were characterised by phylogenetic analysis, selection pressure analysis, prediction of potential glycosylation sites and phylodynamic analysis of the study strains.
RESULTS
The study strains belonged to genogroup 6B. A total of 12 mutations were observed, half of which were located on the key receptor binding region of the HA1 protein. Established virulence markers D222G, S183P were observed in 2017 samples. Acquisition of an extra glycosylation site was observed in few strains from 2017 and 2016. Selection pressure analysis found the average dN/dS (v) ratio of 0.2106 and few codon sites in particular showed significant evidence of being under negative selection.
CONCLUSION
The genogroup 6B continues to be the dominant circulating strain in Indian subcontinent region however the presence of pathogenic mutations in the 2017 strains from north India underlines the importance of continued molecular surveillance.
PubMed: 38854978
DOI: 10.18502/ijm.v16i2.15358