Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Oligosaccharide Assembly01:24

Oligosaccharide Assembly

2.9K
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
2.9K
Drug Metabolism: Phase II Reactions01:14

Drug Metabolism: Phase II Reactions

3.9K
Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...
3.9K
Protein Modifications in the RER01:26

Protein Modifications in the RER

5.4K
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
5.4K
Protein Glycosylation01:25

Protein Glycosylation

7.1K
Glycosylation, the most common post-translational modification for proteins, serves diverse functions. Adding sugars to proteins makes the proteins more resistant to proteolytic digestion. Glycosylated proteins can act as markers and receptors to promote cell-cell adhesion. Additionally, they have many essential quality control functions in the cell, such as correct protein folding and facilitating transport of misfolded proteins to the cytosol, which can be degraded.
Glycosylation occurs in...
7.1K
Ligand Binding and Linkage00:49

Ligand Binding and Linkage

4.8K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.8K
Proteoglycans01:05

Proteoglycans

4.0K
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
4.0K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Oncological Outcomes of Non-Muscle Invasive Bladder Cancer in Patients Aged ≤45: A Retrospective Matched Cohort Study.

The Journal of urology·2026
Same author

Extensively hydrolyzed versus intact milk protein formula and risk of necrotizing enterocolitis: a meta-analysis.

Frontiers in pediatrics·2026
Same author

Factors That Impact In-Patients Use of an App: An Exploratory Study.

Studies in health technology and informatics·2026
Same author

Synthesis and biophysical evaluation of C-5-triazolyl-functionalized morpholino-thymidine analogs.

Organic & biomolecular chemistry·2026
Same author

Acyclic serinol nucleic acid modification of siRNAs overcomes seed region mediated off-target effects while maintaining potency.

Nucleic acids research·2026
Same author

A metal ion-dependent mechanism promoting gain of function in NEIL1 variants.

International journal of radiation biology·2026
Same journal

Development of Indole-3-yl-methylene-thiobarbital Derivatives as Inhibitors of HDAC8 Enzyme Activity.

Journal of medicinal chemistry·2026
Same journal

Discovery of a Potent NAMPT-Targeting PROTAC for the Suppression of Triple-Negative Breast Cancer via Macrophage Reprogramming.

Journal of medicinal chemistry·2026
Same journal

3',4'-Isopropylidene-α-galactosylceramide Enables Multidose Th1 Adjuvanticity Despite Limited Serial Serum IFN-γ Responsiveness.

Journal of medicinal chemistry·2026
Same journal

A Bioorthogonally Cleavable <i>N</i>-Oxide Linker for Prodrug Design: Elucidating the Structure-Cyclization Kinetics Relationships for Controlled Drug Release.

Journal of medicinal chemistry·2026
Same journal

A Melatonin-Catechol Hybrid Molecule Prolongs Lifespan via Regulating ROS and Reprogramming Mitochondrial Metabolism.

Journal of medicinal chemistry·2026
Same journal

Discovery of SD-2301 as a Highly Potent and Selective PROTAC STAT3 Degrader Capable of Achieving Complete Tumor Regression with Single Administration.

Journal of medicinal chemistry·2026
See all related articles

Related Experiment Video

Updated: Aug 11, 2025

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides
08:46

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Published on: July 26, 2018

8.8K

Metabolically Stable Anomeric Linkages Containing GalNAc-siRNA Conjugates: An Interplay among ASGPR, Glycosidase, and

Pachamuthu Kandasamy1, Shohei Mori1, Shigeo Matsuda1

  • 1Alnylam Pharmaceuticals, Inc., Cambridge, Massachusetts 02142, United States.

Journal of Medicinal Chemistry
|February 9, 2023
PubMed
Summary
This summary is machine-generated.

Novel N-acetyl-d-galactosamine (GalNAc) ligands improve liver-specific small interfering RNA (siRNA) delivery by resisting in vivo cleavage. Stability of the anomeric linkage is less critical for gene silencing duration than protein-nucleic acid interactions.

More Related Videos

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines
12:06

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines

Published on: November 25, 2017

12.8K
Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy
08:16

Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy

Published on: February 7, 2025

540

Related Experiment Videos

Last Updated: Aug 11, 2025

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides
08:46

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Published on: July 26, 2018

8.8K
Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines
12:06

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines

Published on: November 25, 2017

12.8K
Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy
08:16

Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy

Published on: February 7, 2025

540

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Drug Delivery

Background:

  • Triantennary N-acetyl-d-galactosamine (GalNAc) conjugates facilitate liver-specific uptake of small interfering RNA (siRNA) via the asialoglycoprotein receptor (ASGPR).
  • The natural beta-glycosidic bond in GalNAc ligands is susceptible to rapid in vivo enzymatic cleavage by glycosidases, potentially limiting therapeutic duration.
  • Optimizing GalNAc ligand stability is crucial for enhancing the efficacy and longevity of siRNA-based therapeutics targeting hepatocytes.

Purpose of the Study:

  • To synthesize and evaluate novel GalNAc ligands with modified glycosidic linkages for enhanced stability against glycosidase activity.
  • To assess the impact of these modified ligands on ASGPR binding affinity and in vivo gene silencing efficacy of siRNA conjugates.
  • To determine the critical factors influencing the duration of action for GalNAc-siRNA conjugates beyond the stability of the anomeric linkage.

Main Methods:

  • Synthesis of novel GalNAc ligands, including S-, C-, N-, and O-glycosides with varied anomeric linkages (alpha and beta).
  • Conjugation of synthesized GalNAc ligands to siRNA using on-column or post-synthetic methods.
  • Evaluation of ASGPR binding affinity and in vivo gene silencing activity in mice for the modified siRNA conjugates.

Main Results:

  • Modified GalNAc ligands demonstrated resistance to glycosidase activity in vitro, unlike the natural GalNAc ligand.
  • siRNA conjugates with novel GalNAc ligands exhibited comparable ASGPR binding affinities and liver-specific gene silencing activities in mice to the parent GalNAc-siRNA conjugate.
  • The stereochemistry and stability of the anomeric linkage were found to be less critical for the duration of action compared to protein-nucleic acid interactions and RISC loading.

Conclusions:

  • Novel GalNAc ligands offer improved stability against enzymatic degradation, maintaining liver-targeting and gene silencing capabilities.
  • Factors beyond the GalNAc ligand's anomeric linkage stability, such as protein-nucleic acid interactions and RISC loading, are key determinants of siRNA therapeutic duration.
  • These findings provide insights for designing more robust and effective GalNAc-conjugated siRNA therapeutics for liver diseases.