The present approach would greatly accelerate the discovery research of new class autoantibodies as well as the development of therapeutic mAbs reacting specifically with disease-relevant epitopes.
The conformational impact of the clustered O-glycans strongly influences recognition by antibodies of the cancer-relevant epitope in the MUC1 extracellular tandem repeat domain.
A potent inhibitor for Vibrio cholerae neuraminidase (VCNA) was developed by using a novel two-step strategy, a target amino acid validation using mechanism-based labeling information, and a potent inhibitor search using a focused library. The labeling information suggested the hidden dynamics of a loop structure of VCNA, which can be a potential target of the novel inhibitor. A focused library composed of 187 compounds was prepared from a 9-azide derivative of 2,3-dehydro-N-acetylneuraminic acid (DANA) to interrupt the function of the loop of the labeled residues. Inhibitor 3 c showed potent inhibition properties and was the strongest inhibitor with FANA, a N-trifluoroacetyl derivative of DANA. Validation studies of the inhibitor with a detergent and a Lineweaver-Burk plot suggested that the 9-substitution group would interact hydrophobically with the target loop moiety, adding a noncompetitive inhibition property to the DANA skeleton. This information enabled us to design compound 4 having the combined structure of 3 c and FANA. Compound 4 showed the most potent inhibition (K(i) =73 nM, mixed inhibition) of VCNA with high selectivity among the tested viral, bacterial, and mammal neuraminidases.
Glycans attached to the IgG Fc domain affect strongly biological activities such as antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) of therapeutic antibodies. However, molecular mechanism in the glycoform-dependent functional modulation of the IgGs remains elusive. The present study communicates that selected reaction monitoring (SRM)-based assay of tryptic IgG Fc glycopeptides is a promising approach for the characterization of antibodies when combined with structure-defined synthetic Fc peptides having a focused -glycoform as a calibration standard. We describe a novel synthetic approach to the human IgG1 Fc peptide having a bisected decasaccharide and its nonbisected counterpart compound, the signatures of antibodies involving Fc domain with rare-glycans expected to show much higher ADCC/CDC than abundant IgG -glycans, and their application to the SRM-based quantitative glycoproteomics. Use of a key intermediate, phenyl (2--benzyl-4,6--benzylidine-β-d-mannopyranosyl)-(1 → 4)-3,6-di--benzyl-2-azido-2-deoxy-1-thio-β-d-glucopyranoside, derived from locust bean gum galactomannan, facilitated greatly the synthesis of a bisected nonasaccharide as a stable precursor of oxazoline derivative needed for the enzymatic -glycosylation with Fc nonapeptide carrying a GlcNAc at Asn297 residue, while the coupling reaction catalyzed by mutant endo-M-N175Q proceeded very slowly. Strikingly, SRM assay using the synthetic Fc glycopeptides as calibration standards uncovered the occurrence of the targeted IgG1 Fc fragment carrying a nonfucosylated and bisected (315 fmol, 0.20%) and its nonbisected counterpart (1154 fmol, 0.73%) in the tryptic digests from 158 pmol of anticancer antibody Herceptin (trastuzumab). The results suggest that aberrantly glycosylated IgG Fc variants may contribute to the total biological activities of the therapeutic antibodies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.