3wwg: Difference between revisions

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== Function ==

[[http://www.uniprot.org/uniprot/IPUA_ASPNG 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<ref>PMID:25359784</ref>

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>

</div>

== References ==

__TOC__

</StructureSection>

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 == Function ==
 [[http://www.uniprot.org/uniprot/IPUA_ASPNG 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).
+<div style="background-color:#fffaf0;">
+== 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<ref>PMID:25359784</ref>
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
+</div>
+== References ==
+<references/>
 __TOC__
 </StructureSection>