1l7k
From Proteopedia
(New page: 200px<br /><applet load="1l7k" size="450" color="white" frame="true" align="right" spinBox="true" caption="1l7k, resolution 1.95Å" /> '''x-ray structure of g...) |
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| - | [[Image:1l7k.gif|left|200px]]<br /><applet load="1l7k" size=" | + | [[Image:1l7k.gif|left|200px]]<br /><applet load="1l7k" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1l7k, resolution 1.95Å" /> | caption="1l7k, resolution 1.95Å" /> | ||
'''x-ray structure of galactose mutarotase from Lactococcus lactis complexed with galactose'''<br /> | '''x-ray structure of galactose mutarotase from Lactococcus lactis complexed with galactose'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Galactose mutarotase plays a key role in normal galactose metabolism by | + | Galactose mutarotase plays a key role in normal galactose metabolism by catalyzing the interconversion of beta-D-galactose and alpha-D-galactose. Here we describe the three-dimensional architecture of galactose mutarotase from Lactococcus lactis determined to 1.9-A resolution. Each subunit of the dimeric enzyme displays a distinctive beta-sandwich motif. This tertiary structural element was first identified in beta-galactosidase and subsequently observed in copper amine oxidase, hyaluronate lyase, chondroitinase, and maltose phosphorylase. Two cis-peptides are found in each subunit, namely Pro(67) and Lys(136). The active site is positioned in a rather open cleft, and the electron density corresponding to the bound galactose unequivocally demonstrates that both anomers of the substrate are present in the crystalline enzyme. Those residues responsible for anchoring the sugar to the protein include Arg(71), His(96), His(170), Asp(243), and Glu(304). Both His(96) and His(170) are strictly conserved among mutarotase amino acid sequences determined thus far. The imidazole nitrogens of these residues are located within hydrogen bonding distance to the C-5 oxygen of galactose. Strikingly, the carboxylate group of Glu(304) is situated at approximately 2.7 A from the 1'-hydroxyl group of galactose, thereby suggesting its possible role as a general acid/base group. |
==About this Structure== | ==About this Structure== | ||
| - | 1L7K is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lactococcus_lactis Lactococcus lactis] with GLA and NA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aldose_1-epimerase Aldose 1-epimerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.1.3.3 5.1.3.3] Full crystallographic information is available from [http:// | + | 1L7K is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lactococcus_lactis Lactococcus lactis] with <scene name='pdbligand=GLA:'>GLA</scene> and <scene name='pdbligand=NA:'>NA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aldose_1-epimerase Aldose 1-epimerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.1.3.3 5.1.3.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1L7K OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Lactococcus lactis]] | [[Category: Lactococcus lactis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Holden, H | + | [[Category: Holden, H M.]] |
| - | [[Category: Thoden, J | + | [[Category: Thoden, J B.]] |
[[Category: GLA]] | [[Category: GLA]] | ||
[[Category: NA]] | [[Category: NA]] | ||
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[[Category: mutarotase]] | [[Category: mutarotase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:42:11 2008'' |
Revision as of 11:42, 21 February 2008
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x-ray structure of galactose mutarotase from Lactococcus lactis complexed with galactose
Overview
Galactose mutarotase plays a key role in normal galactose metabolism by catalyzing the interconversion of beta-D-galactose and alpha-D-galactose. Here we describe the three-dimensional architecture of galactose mutarotase from Lactococcus lactis determined to 1.9-A resolution. Each subunit of the dimeric enzyme displays a distinctive beta-sandwich motif. This tertiary structural element was first identified in beta-galactosidase and subsequently observed in copper amine oxidase, hyaluronate lyase, chondroitinase, and maltose phosphorylase. Two cis-peptides are found in each subunit, namely Pro(67) and Lys(136). The active site is positioned in a rather open cleft, and the electron density corresponding to the bound galactose unequivocally demonstrates that both anomers of the substrate are present in the crystalline enzyme. Those residues responsible for anchoring the sugar to the protein include Arg(71), His(96), His(170), Asp(243), and Glu(304). Both His(96) and His(170) are strictly conserved among mutarotase amino acid sequences determined thus far. The imidazole nitrogens of these residues are located within hydrogen bonding distance to the C-5 oxygen of galactose. Strikingly, the carboxylate group of Glu(304) is situated at approximately 2.7 A from the 1'-hydroxyl group of galactose, thereby suggesting its possible role as a general acid/base group.
About this Structure
1L7K is a Single protein structure of sequence from Lactococcus lactis with and as ligands. Active as Aldose 1-epimerase, with EC number 5.1.3.3 Full crystallographic information is available from OCA.
Reference
High resolution X-ray structure of galactose mutarotase from Lactococcus lactis., Thoden JB, Holden HM, J Biol Chem. 2002 Jun 7;277(23):20854-61. Epub 2002 Mar 20. PMID:11907040
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