1d6p
| |||||||
| , resolution 2.23Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Lysozyme, with EC number 3.2.1.17 | ||||||
| Related: | 1REY, 1D6Q
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
HUMAN LYSOZYME L63 MUTANT LABELLED WITH 2',3'-EPOXYPROPYL N,N'-DIACETYLCHITOBIOSE
OverviewOverview
The synergism between apolar and polar interactions in the carbohydrate recognition by human lysozyme (HL) was probed by site-directed mutagenesis and affinity labeling. The three-dimensional structures of the Tyr63-->Leu mutant HL labeled with 2',3'-epoxypropyl beta-glycoside of N,N'-diacetylchitobiose (L63-HL/NAG-NAG-EPO complex) and the Asp102-->Glu mutant HL labeled with the 2',3'-epoxypropyl beta-glycoside of N-acetyllactosamine were revealed by X-ray diffraction at 2.23 and 1.96 A resolution, respectively. Compared to the wild-type HL labeled with the 2', 3'-epoxypropyl beta-glycoside of N,N'-diacetylchitobiose, the N-acetylglucosamine residue at subsite B of the L63-HL/NAG-NAG-EPO complex markedly moved away from the 63rd residue, with substantial loss of hydrogen-bonding interactions. Evidently, the stacking interaction with the aromatic side chain of Tyr63 is essential in positioning the N-acetylglucosamine residue in the productive binding mode. On the other hand, the position of the galactose residue in subsite B of HL is almost unchanged by the mutation of Asp102 to Glu. Most hydrogen bonds, including the one between the carboxylate group of Glu102 and the axial 4-OH group of the galactose residue, were maintained by local movement of the backbone from residues 102-104. In both structures, the conformation of the disaccharide was conserved, reflecting an intrinsic conformational rigidity of the disaccharides. The structural analysis suggested that CH-pi interactions played an important role in the recognition of the carbohydrate residue at subsite B of HL.
About this StructureAbout this Structure
1D6P is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Protein-carbohydrate interactions in human lysozyme probed by combining site-directed mutagenesis and affinity labeling., Muraki M, Harata K, Sugita N, Sato KI, Biochemistry. 2000 Jan 18;39(2):292-9. PMID:10630988
Page seeded by OCA on Sun Mar 30 19:35:43 2008