Structural highlights
1nxc is a 1 chain structure with sequence from Lk3 transgenic mice. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | , , , |
| Gene: | man1a (LK3 transgenic mice) |
| Activity: | Mannosyl-oligosaccharide 1,2-alpha-mannosidase, with EC number 3.2.1.113 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN |
Function
[MA1A1_MOUSE] Involved in the maturation of Asn-linked oligosaccharides. Progressively trim alpha-1,2-linked mannose residues from Man(9)GlcNAc(2) to produce Man(5)GlcNAc(2).
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
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.
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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tempel W, Karaveg K, Liu ZJ, Rose J, Wang BC, Moremen KW. Structure of mouse Golgi alpha-mannosidase IA reveals the molecular basis for substrate specificity among class 1 (family 47 glycosylhydrolase) alpha1,2-mannosidases. J Biol Chem. 2004 Jul 9;279(28):29774-86. Epub 2004 Apr 21. PMID:15102839 doi:10.1074/jbc.M403065200
