1edt | pdb_00001edt
CRYSTAL STRUCTURE OF ENDO-BETA-N-ACETYLGLUCOSAMINIDASE H AT 1.9 ANGSTROMS RESOLUTION: ACTIVE SITE GEOMETRY AND SUBSTRATE RECOGNITION
Structural highlights
Function[EBAG_STRPL] Cleaves asparagine-linked oligomannose and hybrid, but not complex, oligosaccharides from glycoproteins. 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 PubMedBACKGROUND: Endo-beta-N-acetylglucosaminidase H (Endo H), an endoglycosidase secreted by Streptomyces plicatus, hydrolyzes the glycosidic bond between the core N-acetyglucosamine residues of asparagine-linked high-mannose oligosaccharides. Endo H is a commonly used reagent in glycobiology research, including the characterization of oligosaccharides in glycoproteins. On-going crystallographic studies of Endo H and related endoglycosidases are aimed at identifying the molecular features that determine the different substrate specificities of these enzymes. RESULTS: The three-dimensional structure of Endo H has been determined to 1.9 A resolution. The overall fold of the enzyme is that of an irregular (alpha/beta)8-barrel comprising eight beta-strand/loop/alpha-helix units. Units 5 and 6 have very short loop sections at the top of the molecule and their alpha-helices are replaced by sections of extended geometry. The loop of unit 2 includes a small two-stranded antiparallel beta-sheet. A shallow curved cleft runs across the surface of the molecule from the area of units 5 and 6, over the core of the beta-barrel to the area of the beta-sheet of loop 2. This cleft contains the putative catalytic residues Asp130 and Glu132 above the core of the beta-barrel. These residues are surrounded by several aromatic residues. The loop 2 area of the cleft is formed by neutral polar residues, mostly asparagines. CONCLUSIONS: The structure of Endo H is very similar to that of Endo F1, a closely related endoglycosidase secreted by Flavobacterium meningosepticum. Detailed comparison of the structures of Endo H and Endo F1 supports the model previously proposed for substate binding and recognition, in which the area of loop 2 determines the substrate specificity and the alpha-helices of units 5 and 6 are missing to accommodate the protein moiety of the substrate. Crystal structure of endo-beta-N-acetylglucosaminidase H at 1.9 A resolution: active-site geometry and substrate recognition.,Rao V, Guan C, Van Roey P Structure. 1995 May 15;3(5):449-57. PMID:7663942[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||
