1m7x
From Proteopedia
(New page: 200px<br /><applet load="1m7x" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m7x, resolution 2.3Å" /> '''The X-ray Crystallogr...) |
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| - | [[Image:1m7x.jpg|left|200px]]<br /><applet load="1m7x" size=" | + | [[Image:1m7x.jpg|left|200px]]<br /><applet load="1m7x" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1m7x, resolution 2.3Å" /> | caption="1m7x, resolution 2.3Å" /> | ||
'''The X-ray Crystallographic Structure of Branching Enzyme'''<br /> | '''The X-ray Crystallographic Structure of Branching Enzyme'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Branching enzyme catalyzes the formation of alpha-1,6 branch points in | + | Branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch. We report the 2.3-A crystal structure of glycogen branching enzyme from Escherichia coli. The enzyme consists of three major domains, an NH(2)-terminal seven-stranded beta-sandwich domain, a COOH-terminal domain, and a central alpha/beta-barrel domain containing the enzyme active site. While the central domain is similar to that of all the other amylase family enzymes, branching enzyme shares the structure of all three domains only with isoamylase. Oligosaccharide binding was modeled for branching enzyme using the enzyme-oligosaccharide complex structures of various alpha-amylases and cyclodextrin glucanotransferase and residues were implicated in oligosaccharide binding. While most of the oligosaccharides modeled well in the branching enzyme structure, an approximate 50 degrees rotation between two of the glucose units was required to avoid steric clashes with Trp(298) of branching enzyme. A similar rotation was observed in the mammalian alpha-amylase structure caused by an equivalent tryptophan residue in this structure. It appears that there are two binding modes for oligosaccharides in these structures depending on the identity and location of this aromatic residue. |
==About this Structure== | ==About this Structure== | ||
| - | 1M7X is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/1,4-alpha-glucan_branching_enzyme 1,4-alpha-glucan branching enzyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.18 2.4.1.18] Full crystallographic information is available from [http:// | + | 1M7X is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/1,4-alpha-glucan_branching_enzyme 1,4-alpha-glucan branching enzyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.18 2.4.1.18] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M7X OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Abad, M | + | [[Category: Abad, M C.]] |
| - | [[Category: Arni, R | + | [[Category: Arni, R K.]] |
[[Category: Binderup, K.]] | [[Category: Binderup, K.]] | ||
| - | [[Category: Geiger, J | + | [[Category: Geiger, J H.]] |
[[Category: Preiss, J.]] | [[Category: Preiss, J.]] | ||
[[Category: Rios-Steiner, J.]] | [[Category: Rios-Steiner, J.]] | ||
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[[Category: beta sandwich]] | [[Category: beta sandwich]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:52:27 2008'' |
Revision as of 11:52, 21 February 2008
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The X-ray Crystallographic Structure of Branching Enzyme
Overview
Branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch. We report the 2.3-A crystal structure of glycogen branching enzyme from Escherichia coli. The enzyme consists of three major domains, an NH(2)-terminal seven-stranded beta-sandwich domain, a COOH-terminal domain, and a central alpha/beta-barrel domain containing the enzyme active site. While the central domain is similar to that of all the other amylase family enzymes, branching enzyme shares the structure of all three domains only with isoamylase. Oligosaccharide binding was modeled for branching enzyme using the enzyme-oligosaccharide complex structures of various alpha-amylases and cyclodextrin glucanotransferase and residues were implicated in oligosaccharide binding. While most of the oligosaccharides modeled well in the branching enzyme structure, an approximate 50 degrees rotation between two of the glucose units was required to avoid steric clashes with Trp(298) of branching enzyme. A similar rotation was observed in the mammalian alpha-amylase structure caused by an equivalent tryptophan residue in this structure. It appears that there are two binding modes for oligosaccharides in these structures depending on the identity and location of this aromatic residue.
About this Structure
1M7X is a Single protein structure of sequence from Escherichia coli. Active as 1,4-alpha-glucan branching enzyme, with EC number 2.4.1.18 Full crystallographic information is available from OCA.
Reference
The X-ray crystallographic structure of Escherichia coli branching enzyme., Abad MC, Binderup K, Rios-Steiner J, Arni RK, Preiss J, Geiger JH, J Biol Chem. 2002 Nov 1;277(44):42164-70. Epub 2002 Aug 23. PMID:12196524
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