1nxc

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spinqualitylabelsall models 1nxc, resolution 1.51Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of mouse Golgi alpha-1,2-mannosidase IA reveals the molecular basis for substrate specificity among Class I enzymes (family 47 glycosidases)

Overview

Three subfamilies of mammalian Class 1 processing alpha1,2-mannosidases, (family 47 glycosidases) play critical roles in the maturation of, Asn-linked glycoproteins in the endoplasmic reticulum (ER) and Golgi, complex as well as influencing the timing and recognition for disposal of, terminally unfolded proteins by ER-associated degradation. In an effort to, define the structural basis for substrate recognition among Class 1, mannosidases, we have crystallized murine Golgi mannosidase IA (space, group P2(1)2(1)2(1)), and the structure was solved to 1.5-A resolution by, molecular replacement. The enzyme assumes an (alphaalpha)(7) barrel, structure with a Ca(2+) ion coordinated at the base of the barrel similar, to other Class 1 mannosidases. Critical residues within the barrel, structure that coordinate the Ca(2+) ion or presumably bind and catalyze, the hydrolysis of the glycone are also highly conserved. A Man(6)GlcNAc(2), oligosaccharide attached to Asn(515) in the murine enzyme was found to, extend into the active site of an adjoining protein unit in the crystal, lattice in a presumed enzyme-product complex. In contrast to an analogous, complex previously isolated for Saccharomyces cerevisiae ER mannosidase I, the oligosaccharide in the active site of the murine Golgi enzyme assumes, a different conformation to present an alternate oligosaccharide branch, into the active site pocket. A comparison of the observed, protein-carbohydrate interactions for the murine Golgi enzyme with the, binding cleft topologies of the other family 47 glycosidases provides a, framework for understanding the structural basis for substrate recognition, among this class of enzymes.

About this Structure

1NXC is a Single protein structure of sequence from Mus musculus with MAN and CA as ligands. Active as Mannosyl-oligosaccharide 1,2-alpha-mannosidase, with EC number 3.2.1.113 Full crystallographic information is available from OCA.

Reference

Structure of mouse Golgi alpha-mannosidase IA reveals the molecular basis for substrate specificity among class 1 (family 47 glycosylhydrolase) alpha1,2-mannosidases., Tempel W, Karaveg K, Liu ZJ, Rose J, Wang BC, Moremen KW, J Biol Chem. 2004 Jul 9;279(28):29774-86. Epub 2004 Apr 21. PMID:15102839

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