Triantennary

Scheme 13.18 JV-linked glycopeptide with a triantennary structure.

Figure 14.3 Structure models of four different conformer populations (2 for each 1—>6 link) of a triantennary high-mannose undecasaccharide M9. Terminal mannoses are highlighted as CPK models.12...

The flexibility of the sugar linkages in glycoproteins results in multiple conformations that can be detected by time-resolved fluorescence experiments. Figure B9.1.1 shows an example of a triantennary glycopeptide labeled with a... 

Fig. B9.1.1. Distance distribution of a triantennary glycopeptide reflecting the multiple conformations (adapted from Wu et al. ).

Scheme 47 Glycopeptide Assembly with Triantennary Building Block 1491...

The triantennary glycan structure of the membrane glycoprotein of vesicular stomatitis virus (New Jersey serotype) has been elucidated by Ballou and coworkers215 (see Fig. 38). 

Branch point disaccharide of triantennary and tetraantennary oligosaccharide P-d-GIcAI Ac... 

Fig. 2. iV-glycans of the hybrid type. A triantennary structure with sialylated Af-acetyllactosamine (LacNAc) building blocks B biantennary structure with sialylated or fucosylated poly-LacNAc building blocks. The N-glycan core structure is written in bold letters... 

In 1998, Morten Meldal and coworkers demonstrated the semisynthesis of Asn derivatives of complex-type bi- and triantennary asialo N-glycans [58], After isolation of these oligosaccharides from the glycoproteins fetuin and ribonuclease (RNase) B by hydrazinolysis, the glycans were converted to Fmoc-Asn(oligosaccharide)-OH derivatives with an acetylated sugar part. In 2003, the Yasuhiro Kajihara group... 

Compound 9 is a triantennary, asialo glycopeptide that can be isolated from various desialylated glycoproteins.1-4 The 500-MHz, H-n.m.r. spectrum of 9, derived from a,-acid glycoprotein,66-69 is given in Fig. 9, and the n.m.r. parameters are compiled in Table V. The spectral features of this glycopeptide bear a high similarity to those of compound 8 (see Table V). 

Compound 30 is a triantennary, sialo oligosaccharide terminated with NeuAc a-(2- 6)-linked to Gal in the three branches. It has been... 

It must be emphasized that the extension of a triantennary structure with a NeuAc group a-(2— 6)-linked to Gal-8 can be unambiguously established on the basis of both the unique set of chemical shifts for its H-3c, H-3e, and N-acetyl protons, as well as its specific effects upon the chemical shifts of the structural-reporter groups of GlcNAe-7 and Gal-8 (compare Table XIII). 

Compound 34 is a triantennary, sialo glycopeptide terminated with NeuAc a-(2- 6)-linked to Gal in all three branches it could be obtained by exhaustive, in vitro sialylation of compound 9 with /3-D-ga-lactoside a-(2— 6)-sialyltransferase.13,78 The Gln-Asn analog of compound 34, in admixture with compound 53 and a glycopeptide analog of 41, has been isolated from human-plasma ceruloplasmin (see compound 53). The 500-MHz, -n.m.r. spectrum of 34 is given in Fig. 26, and its pertinent spectral parameters are listed in Table X. 

Compound 41 is a triantennary, sialo oligosaccharide possessing a-(2— 6)-l inked NeuAc groups in the terminal position of both /3-(l— 2)-linked N-acetyllactosamine branches, and an a-(2— 3)-linked NeuAc as the terminating group of the /8-(l— 4)-linked part. Compound 41 was available as the main component (92%) of a mixture of two oligo-... 

The triantennary type of branching of the trimannosyl part of the oligosaccharide was established on the basis of the chemical shifts of the H-l and H-2 signals of Man-3, -4, and -4, taking into consideration the shift effects upon these due to extension of both the 5-6 and the 5 -6 branch with NeuAc in a-(2— 6) linkage (compare Tables VI and XIII see also, compound 30). 

Compound 48 is a triantennary glycopeptide containing a terminal Fuc group a-(l— 3)-linked to GlcNAc-7. This compound was derived from asialo aracid glycoprotein67-8 (peptide moiety Asn-Lys) and from asialo ceruloplasmin84 (peptide moiety Asn). The 500-MHz, H-n.m.r. spectrum of the glycopeptide obtained from the latter source is shown in Fig. 35 its spectral parameters are listed in Table XVI. 

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