3a3q

Structure of N59D HEN EGG-WHITE LYSOZYME in complex with (GlcNAc)3

spinqualitylabelsall models 3a3q, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3a3q is a 1 chain structure with sequence from Chick. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NAG Related: 1lza, 3a3r Activity: Lysozyme, with EC number 3.2.1.17 Resources: FirstGlance, OCA, RCSB, PDBsum Function [LYSC_CHICK] Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Has bacteriolytic activity against M.luteus. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed In the catalysis of sugar hydrolysis by hen egg-white lysozyme, Asp52 is thought to stabilize the reaction intermediate. This residue is involved in the well-ordered hydrogen bonding network including Asn46, Asp48, Ser50 and Asn59 on the anti-parallel beta-sheet, designated as a 'platform', on which the substrate sugar sits. To reveal the role of this hydrogen bonding network in the hydrolysis, we characterized Asn59 mutants by biochemical and crystallographic studies. Surprisingly, the introduction of only a methylene group by the Asn59Gln mutation markedly reduced the bacteriolytic activity and abolished the hydrolytic activity towards the synthetic substrate, PNP-(GlcNAc)(5). A similar result was also obtained with the Asn59Asp mutant. The crystal structure of the Asn59Asp mutant in complex with the substrate analogue revealed that, as in the wild-type, the (GlcNAc)(3) was bound in the A-B-C subsites. The reduced activity would be caused by subtle changes in the side-chain orientations as well as the electrostatic characteristics of Asp59, resulting in the rearrangement of the hydrogen bonding network of the platform. These results suggest that the precise locations of these 'platform' residues, maintained by the well-ordered hydrogen bonding network, are crucial for efficient hydrolysis. Importance of the hydrogen bonding network including Asp52 for catalysis, as revealed by Asn59 mutant hen egg-white lysozymes.,Ose T, Kuroki K, Matsushima M, Maenaka K, Kumagai I J Biochem. 2009 Nov;146(5):651-7. Epub 2009 Jul 15. PMID:19605465 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lysozyme 3D structures

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