Insights into the role of the aromatic residue in galactose-binding sites: MP2/6-311G++** study on galactose- and glucose-aromatic residue analogue complexes
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Title |
Insights into the role of the aromatic residue in galactose-binding sites: MP2/6-311G++** study on galactose- and glucose-aromatic residue analogue complexes
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Creator |
SUJATHA, MS
SASIDHAR, YU BALAJI, PV |
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Subject |
cation-pi interactions
ricin-b chain crystal-structures hydrogen-bonds carbohydrate-binding computational design fluorodeoxy sugars 2-gamma subdomain escherichia-coli lectin structure |
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Description |
The presence of an aromatic residue (Trp, Phe, Tyr) facing the nonpolar face of galactose is a common feature of galactose-specific lectins. The interactions such as those between the C-H groups of galactose and the pi-electron cloud of aromatic residues have been characterized as weak hydrogen bonds between soft acids and soft bases, largely governed by dispersive and charge transfer interactions, An analysis of the binding sites of several galactose-specific lectins revealed that the spatial position-orientation of galactose relative to the binding site aromatic residue varies substantially. The effect of variations in position-orientations of galactose on the interaction energies of galactose-aromatic residue complexes has not been determined so far. In view of this, MP2/6-311G++** calculations were performed on galactose- and glucose-aromatic residue analogue complexes in eight position-orientations. The results show that the strength of the C-H... it interactions in galactose-aromatic residue complexes is comparable to that of a hydrogen bond. Rather than the type of aromatic residue, the position-orientation of the saccharide appears to be more critical in determining the strength of their interactions. Earlier studies have found the binding site aromatic residue to be critical, but its role was not clear, This study shows that the aromatic residue is important for discriminating galactose from glucose, in addition to its contribution to binding energy.
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Publisher |
AMER CHEMICAL SOC
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Date |
2011-07-14T08:28:07Z
2011-12-26T12:48:17Z 2011-12-27T05:48:04Z 2011-07-14T08:28:07Z 2011-12-26T12:48:17Z 2011-12-27T05:48:04Z 2005 |
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Type |
Article
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Identifier |
BIOCHEMISTRY, 44(23), 8554-8562
0006-2960 http://dx.doi.org/10.1021/bi050298b http://dspace.library.iitb.ac.in/xmlui/handle/10054/3909 http://hdl.handle.net/10054/3909 |
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Language |
en
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