N-Glycan Modifications with Negative Charge in a Natural Polymer Mucin from Bovine Submaxillary Glands, and Their Structural Role

Abstract

Bovine submaxillary mucin (BSM) is a natural polymer used in biomaterial applications for its viscoelasticity, lubricity, biocompatibility, and biodegradability. N-glycans are important for mucin stability and function, but their structures have not been fully characterized, unlike that of O-glycans. In this study, BSM N-glycans were investigated using liquid chromatography-tandem mass spectrometry. The microheterogeneous structures of 32 N-glycans were identified, and the quantities (%) of each N-glycan relative to total N-glycans (100%) were obtained. The terminal N-acetylgalactosamines in 12 N-glycans (sum of relative quantities; 27.9%) were modified with mono- (10 glycans) and disulfations (2 glycans). Total concentration of all sulfated N-glycans was 6.1 pmol in BSM (20 µg), corresponding to 25.3% of all negatively charged glycans (sum of present N-glycans and reported O-glycans). No N-glycans with sialylated or phosphorylated forms were identified, and sulfate modification ions were the only negative charges in BSM N-glycans. Mucin structures, including sulfated N-glycans located in the hydrophobic terminal regions, were indicated. This is the first study to identify the structures and quantities of 12 sulfated N-glycans in natural mucins. These sulfations play important structural roles in hydration, viscoelasticity control, protection from bacterial sialidases, and polymer stabilization to support the functionality of BSM via electrostatic interactions.

Interplay between biofilm microenvironment and pathogenicity of Pseudomonas aeruginosa in cystic fibrosis lung chronic infection

“…Mucins have a huge binding capacity because of the simultaneous presence of hydrophilic, hydrophobic, and negatively charged domains. Lipophilic drugs interact with some of the peptide parts of mucins (i.e., CysK, VWD, CysD); hydrophilic molecules engage mucins either through H-bonding or, if positively charged, by electrostatic interactions on the negatively charged carbohydrate chains [ 101 , 102 ]. Such a complex filtering activity can impact the efficacy of pharmaceuticals in eradicating PA infection.…”

Development of Triamcinolone Acetonide Loaded Poly(lactide-co-glycolic acid) Dry Powder Inhaler Formulations For The Treatment of Asthma

“…Similar results established by Han et al (23). The charge on the respiratory system is negative owing to mucin (24). Negative charge on the respiratory system and negative charged DPI microparticles could It is essential to assure that the microparticles might be potentially delivered to the pulmonary route as the target organ.…”

Labeling of Mucin-Type O-Glycans for Quantification Using Liquid Chromatography and Fluorescence Detection

“…However, they are often purely qualitative because the abundance of specific glycan signals is linked to not only their concentration but also their ionization efficiency and the sample matrix. Therefore, MS-based techniques are only semiquantitative, and methods for direct quantification of O -glycans are urgently needed to gain a better understanding of the underlying biological O -glycosylation processes, which are important in studying disease progression. , While the use of fluorescence labeling and FLD is a standard technique in N -glycomics, − examples for O -glycan analysis remain scarce. First efforts linking fluorescence labeling to O -glycan analysis have been described recently. − However, a complete study demonstrating its potential for the quantification of complex mucin-type O -glycan samples is still lacking.…”