Conformation of sLex Tetrasaccharide, Free in Solution and Bound to E-, P-, and L-Selectin
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- 作者：Leszek Poppe ; Gregory S. Brown ; John S. Philo ; Pandurang V. Nikrad ; and Bhavana H. Shah
- 刊名：Journal of the American Chemical Society
- 出版年：1997
- 出版时间：February 19, 1997
- 年：1997
- 卷：119
- 期：7
- 页码：1727 - 1736
- 全文大小：387K
- 年卷期：v.119,no.7(February 19, 1997)
- ISSN：1520-5126
文摘
The conformations of theNeuAc
2(I)
3Gal
1(II)4[Fuc1(III)3]GlcNAc-O-CH3tetrasaccharide (sLex),in aqueous solution and bound to E-, P-, and L-selectin have beendetermined using high resolution NMR spectroscopy.In the free ligand, the conformation of glycosidic linkage I isdisordered with {
I, 
I} samplingvalues close to{-60
, 0}, {-100, -50}, and {180,0}. The trisaccharide portion is rigid and characterized by{II, II;III,III} = {46, 18; 48, 24}. Themeasured dissociation rates and equilibrium binding constants,{koff, KD},were{164 ± 24 s-1, 0.72 ± 0.4 mM}, {522± 166 s-1, 7.8 ± 1.0 mM}, and {1080± 167 s-1, 3.9 ± 0.6 mM} at300K for E-, P-, and L-selectin, respectively. The boundconformations of the ligand were calculated from the fullrelaxation matrix analysis of transferred-NOE spectra for E- andP-selectin or by using a two-spin approximation forthe L-selectin complex. Both E- and P-selectin recognize the{-60, 0} conformation of sLex while the{-100,-50} conformer is probably recognized by L-selectin. Theconformation of the branched trisaccharide portion inthe bound state remains close to the conformation of the free ligand.In the E-, P-, and L-selectin complexes theGalH4 proton is in the vicinity of protein aromatic protons, mostlikely Tyr94 and/or Tyr48.
2(I)3Gal1(II)4[Fuc1(III)3]GlcNAc-O-CH3tetrasaccharide (sLex),in aqueous solution and bound to E-, P-, and L-selectin have beendetermined using high resolution NMR spectroscopy.In the free ligand, the conformation of glycosidic linkage I isdisordered with {I, I} samplingvalues close to{-60, 0}, {-100, -50}, and {180,0}. The trisaccharide portion is rigid and characterized by{II, II;III,III} = {46, 18; 48, 24}. Themeasured dissociation rates and equilibrium binding constants,{koff, KD},were{164 ± 24 s-1, 0.72 ± 0.4 mM}, {522± 166 s-1, 7.8 ± 1.0 mM}, and {1080± 167 s-1, 3.9 ± 0.6 mM} at300K for E-, P-, and L-selectin, respectively. The boundconformations of the ligand were calculated from the fullrelaxation matrix analysis of transferred-NOE spectra for E- andP-selectin or by using a two-spin approximation forthe L-selectin complex. Both E- and P-selectin recognize the{-60, 0} conformation of sLex while the{-100,-50} conformer is probably recognized by L-selectin. Theconformation of the branched trisaccharide portion inthe bound state remains close to the conformation of the free ligand.In the E-, P-, and L-selectin complexes theGalH4 proton is in the vicinity of protein aromatic protons, mostlikely Tyr94 and/or Tyr48.