Site specific N-glycan profiling of NeuAc(alpha 2-6)-Gal/GalNAc-binding bark Sambucus nigra agglutinin using LC-MSn revealed differential glycosylation

Kumar, Gnanesh B S and Surolia, Avadhesha (2016) Site specific N-glycan profiling of NeuAc(alpha 2-6)-Gal/GalNAc-binding bark Sambucus nigra agglutinin using LC-MSn revealed differential glycosylation. In: GLYCOCONJUGATE JOURNAL, 33 (6). pp. 907-915.

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Abstract

The bark of Sambucus nigra contains a complex mixture of glycoproteins that are characterized as chimeric lectins known as type II ribosome inactivating proteins and holo lectins. These type II ribosome inactivating proteins possess RNA N-glycosidase activity in subunit A and lectin activity associated with subunit B exhibiting distinct sugar specificities to NeuAc(alpha 2-6)-Gal/GalNAc and Gal/GalNAc. In the present study we have determined the N-glycosylation pattern of type II ribosome inactivating protein specific to NeuAc(alpha 2-6)-Gal/GalNAc (Sambucus nigra agglutinin I) by subjecting it to digestion with multiple proteases. The resulting mixture of peptides and N-glycopeptides were analyzed on liquid chromatography coupled to electro spray ionization-iontrap mass spectrometry in MSn mode. MS2 of precursor ions was carried out using CID which provided information on glycan sequence. In subsequent MS3 of Y-1/Y-1 alpha ions (peptide + HexNAc)(+n) of corresponding N-glycopeptides, resulted in the fragmentation of peptide backbone confirming the site of attachment. We observed microheterogeneity in each glycan occupied site with subunit A possessing four N-glycans out of six sites with complex and paucimannose types while subunit B comprises occupancy of two sites with a paucimannose and a high mannose type. The differential N-glycosylation of subunits in SNA is discussed in the context of other type II RIPs glycans.

Item Type:	Journal Article
Publication:	GLYCOCONJUGATE JOURNAL
Additional Information:	Copy right for this article belongs to theSPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	31 Jan 2017 04:37
Last Modified:	31 Jan 2017 04:37
URI:	http://eprints.iisc.ac.in/id/eprint/55969

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