1rem
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HUMAN LYSOZYME WITH MAN-B1,4-GLCNAC COVALENTLY ATTACHED TO ASP53
OverviewOverview
Human lysozyme (HL) labelled with the 2',3'-epoxypropyl beta-glycoside of Man-beta1,4-GlcNAc was crystallized at pH 4.5. The cell dimensions were a = 36.39, b = 116.38, c = 30.91 A and the space group was P212121. The unit cell contained four molecules (Vm = 2.18 A3 Da-1). The crystal structure was determined by molecular replacement and refined to an R value of 0.168 for 7060 reflections [|Fo| > 3sigma(F)] in the resolution range 8.0-2.1 A. A prominent shift of the Calpha-atom positions by up to 3.8 A in the region of residues 45-50 was observed compared with wild-type HL. Owing to the conformational change in this region the intermolecular contacts were altered remarkably compared to wild-type HL, explaining the difference in molecular packing. The Man-beta1,4-GlcNAc moiety occupied subsites B and C in the substrate-binding site of HL. Several differences in the hydrogen-bonded contacts between the ligand part and the protein part were observed for HL labelled with the 2',3'-epoxypropyl beta-glycoside of Man-beta1,4-GlcNAc compared with HL labelled with the corresponding derivatives of GlcNAc-beta1, 4-GlcNAc and Gal-beta1,4-GlcNAc. In contrast to the replacement of GlcNAc with Gal, the replacement of GlcNAc with Man did not sacrifice the stacking interactions with the side-chain group of Tyr63 as determined by the parallelism of the apolar face of the carbohydrate residue and the aromatic plane of the Tyr63 side chain. The 2',3'-epoxypropyl beta-glycoside of Man-beta1,4-GlcNAc exhibited almost the same affinity towards HL as Gal-beta1,4-GlcNAc, a much lower affinity than that of GlcNAc-beta1,4-GlcNAc. The difference in the protein-ligand interactions was discussed in relation to the carbo-hydrate-residue recognition specificity at subsite B of HL. The results suggested that Gln104 was a determinant for the strong recognition of GlcNAc residue at subsite B in HL.
About this StructureAbout this Structure
1REM is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
X-ray structure of human lysozyme labelled with 2',3'-epoxypropyl beta-glycoside of man-beta1,4-GlcNAc. Structural change and recognition specificity at subsite B., Muraki M, Harata K, Sugita N, Sato K, Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):834-43. PMID:9757098
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