American Chemical Society
ja4056678_si_001.pdf (7.92 MB)

‘Naked’ and Hydrated Conformers of the Conserved Core Pentasaccharide of N‑linked Glycoproteins and Its Building Blocks

Download (7.92 MB)
journal contribution
posted on 2015-12-16, 23:51 authored by Conor S. Barry, Emilio J. Cocinero, Pierre Çarçabal, David P. Gamblin, E. Cristina Stanca-Kaposta, Sarah M. Remmert, María C. Fernández-Alonso, Svemir Rudić, John P. Simons, Benjamin G. Davis
N-glycosylation of eukaryotic proteins is widespread and vital to survival. The pentasaccharide unit −Man3GlcNAc2– lies at the protein-junction core of all oligosaccharides attached to asparagine side chains during this process. Although its absolute conservation implies an indispensable role, associated perhaps with its structure, its unbiased conformation and the potential modulating role of solvation are unknown; both have now been explored through a combination of synthesis, laser spectroscopy, and computation. The proximal −GlcNAc-GlcNAc– unit acts as a rigid rod, while the central, and unusual, −Man-β-1,4-GlcNAc– linkage is more flexible and is modulated by the distal Man-α-1,3– and Man-α-1,6– branching units. Solvation stiffens the ‘rod’ but leaves the distal residues flexible, through a β-Man pivot, ensuring anchored projection from the protein shell while allowing flexible interaction of the distal portion of N-glycosylation with bulk water and biomolecular assemblies.