Identification of the S-layer glycoproteins and their covalently linked glycans in the halophilic archaeon Haloarcula hispanica

In this study, the S-layer proteins of Har. hispanica were extracted and characterized. The S-layer was found containing two different glycoproteins which shared highly similar amino acid sequences. The genes coding for these two S-layer glycoproteins were found next to each other in the genome. Moreover, the N- and O-linked glycans were released from these two S-layer glycoproteins for structural determination. Based on the mass spectrometry and nuclear magnetic resonance, the N-glycan was determined as a branched trisaccharide containing a 225 Da residue corresponded to a 2-amino-6-sulfo-2, 6-dideoxy-quinovose, which was the first time that a naturally occurring form of sulfoquinovosamine was identified. Besides, the O-glycan was characterized as a Glcα-1,4-Gal disaccharide by mass spectrometry combined with monosaccharide composition analysis and glycosidase treatment. The determination of the N- and O-glycan structure will be helpful for studying the diverse protein glycosylation pathways in archaea utilizing H. hispanica as a new model.

Source: Glycobiology - October 6, 2015 Category: Biology Authors: Lu, H., Lu, Y., Ren, J., Wang, Z., Wang, Q., Luo, Y., Han, J., Xiang, H., Du, Y., Jin, C. Tags: Analytical Glycobiology Source Type: research