Glycobiology Advance Access originally published online on December 12, 2005
Glycobiology 2006 16(4):343-348; doi:10.1093/glycob/cwj070
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Observation of a unique pattern of bifurcated hydrogen bonds in the crystal structures of the N-glycoprotein linkage region models
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India
1 To whom correspondence should be addressed; e-mail: loganath{at}iitm.ac.in
Received on October 21, 2005; revised on November 29, 2005; accepted on December 9, 2005
Elucidation of the intra- and intermolecular carbohydrate–protein interactions would greatly contribute toward obtaining a better understanding of the structure–function correlations of the protein-linked glycans. The weak interactions involving C–H...O have recently been attracting immense attention in the domain of biomolecular recognition. However, there has been no report so far on the occurrence of C–H...O hydrogen bonds in the crystal structures of models and analogs of N-glycoproteins. We present herein an analysis of C–H...O interactions in the crystal structures of all N-glycoprotein linkage region models and analogs. The study reveals a cooperative network of bifurcated hydrogen bonds consisting of N–H...O and C–H...O interactions seen uniquely for the models. The cooperative network consists of two antiparallel chains of bifurcated hydrogen bonds, one involving N1–H, C2'–H and O1' of the aglycon moiety and the other involving N2–H, C1–H and O1'' of the sugar. Such bifurcated hydrogen bonds between the core glycan and protein are likely to play an important role in the folding and stabilization of proteins.
Key words: carbohydrates / C–H...O interactions / H bonding / N-glycoprotein models and analogs / X-ray diffraction
Dedicated to late Prof. George Alan Jeffrey