3wwg

Crystal structure of the N-glycan-deficient variant N448A of isopullulanase complexed with isopanose

spinqualitylabelsall models 3wwg, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3wwg is a 4 chain structure with sequence from Aspergillus niger. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: BGC, GLC, NAG, PRD_900001 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function IPUA_ASPNG Hydrolyzes pullulan, a linear polymer which is composed of maltotriose units with alpha-1,6 glucosidic linkages, to produce isopanose (Glca1-4Glca1-6Glc). Publication Abstract from PubMed N-glycosylation has been shown to be important for the stability of some glycoproteins. Isopullulanase (IPU), a polysaccharide-hydrolyzing enzyme, is a highly N-glycosylated protein, and IPU deglycosylation results in a decrease in thermostability. To investigate the function of N-glycan in IPU, we focused on an N-glycosylated residue located in the vicinity of the active site, Asn448. The thermostabilities of three IPU variants, Y440A, N448A and S450A, were 0.5-8.4 degrees C lower than the wild-type enzyme. The crystal structure of endoglycosidase H (Endo H)-treated N448A variant was determined. There are four IPU molecules, Mol-A, B, C and D, in the asymmetric unit. The conformation of a loop composed of amino acid residues 435-455 in Mol-C was identical to wild-type IPU, whereas the conformations of this loop in Mol-A, Mol-B and Mol-D were different from each other. These results suggest that the Asn448 side chain is primarily important for the stability of IPU. Our results indicate that mutation of only N-glycosylated Asn residue may lead to incorrect conclusion for the evaluation of the function of N-glycan. Usually, the structures of N-glycosylation sites form an extended configuration in IPU; however, the Asn448 site had an atypical structure that lacked this configuration. The side chain of a glycosylated asparagine residue is important for the stability of isopullulanase.,Miyazaki T, Yashiro H, Nishikawa A, Tonozuka T J Biochem. 2015 Apr;157(4):225-34. doi: 10.1093/jb/mvu065. Epub 2014 Oct 29. PMID:25359784 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA