Sandbox Reserved 301
From Proteopedia
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<ref name="Abad">PMID:12196524</ref> | <ref name="Abad">PMID:12196524</ref> | ||
<ref name="Abad"/> | <ref name="Abad"/> | ||
| - | Escherichia coli Branching Enzyme (BE) (1,4-a-glucan 6-glucosyltransferase)catalyzes the formation of a-1,6 branch points of glycogen. The enzyme contains three domains: a NH2-terminal seven stranded b-sandwich domain, a COOH-terminal domain, and a central a/b-barrel domain containing the enzyme active site. The branching enzyme belongs to the a-amylase family of enzymes. | + | Escherichia coli Branching Enzyme (BE) (1,4-a-glucan 6-glucosyltransferase)catalyzes the formation of a-1,6 branch points of glycogen <ref name="1m7x">. The enzyme contains three domains: a NH2-terminal seven stranded b-sandwich domain, a COOH-terminal domain, and a central a/b-barrel domain containing the enzyme active site <ref name="1m7x">. The branching enzyme belongs to the a-amylase family of enzymes<ref name="1m7x">. |
__TOC__ | __TOC__ | ||
=Function= | =Function= | ||
| - | Branching Enzymes contributes to the structure of startch in plants and glycogen in animals and bacteria by catalyzing the formation of a-1,6 brach points in the polysaccharides. The polysaccharide is cleaved at the a-1,4 glucosidic linkage, yidleing a non-reducing end oligosaccharide chain and subsequent attachment to the a-1,6 position. Branching of polysaccharides increased the number of non-reducing ends which makes glycogen more reactive to synthesis and digestion, alos essential for assuring its solubility in the cell. | + | Branching Enzymes contributes to the structure of startch in plants and glycogen in animals and bacteria by catalyzing the formation of a-1,6 brach points in the polysaccharides. The polysaccharide is cleaved at the a-1,4 glucosidic linkage, yidleing a non-reducing end oligosaccharide chain and subsequent attachment to the a-1,6 position. Branching of polysaccharides increased the number of non-reducing ends which makes glycogen more reactive to synthesis and digestion, alos essential for assuring its solubility in the cell (as shown in Figure 1). |
=Glyogen Storage Disease type IV= | =Glyogen Storage Disease type IV= | ||
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==Central (a/b) Barrel Catalytic Domain== | ==Central (a/b) Barrel Catalytic Domain== | ||
Based on analysis of biochemical and X-Ray structures of apo- (without a substrate bound) and substrate-bound a-amylase and CGT, the catalytic center of of these enzymes have been localized to the residues Tyr300, Asp335, His340, Arg403, Asp405, Glu458, and Asp526 in the E. ''coli'' as shown in <scene name='Sandbox_Reserved_301/Gbe1/2'>Conserved Residues</scene>. These conserved residues are conserved among members of the a-amylase fmaily including Branching enzymes from various organisms. Studies involving site-directed mutanegensis and chemical modifications revealed that Try300 and Glu459 have to be conserved specifically to E. ''coli'' Branching enzyme in order for the enzymatic activity to be functional. | Based on analysis of biochemical and X-Ray structures of apo- (without a substrate bound) and substrate-bound a-amylase and CGT, the catalytic center of of these enzymes have been localized to the residues Tyr300, Asp335, His340, Arg403, Asp405, Glu458, and Asp526 in the E. ''coli'' as shown in <scene name='Sandbox_Reserved_301/Gbe1/2'>Conserved Residues</scene>. These conserved residues are conserved among members of the a-amylase fmaily including Branching enzymes from various organisms. Studies involving site-directed mutanegensis and chemical modifications revealed that Try300 and Glu459 have to be conserved specifically to E. ''coli'' Branching enzyme in order for the enzymatic activity to be functional. | ||
| - | <scene name='Sandbox_Reserved_301/Conserved_residues/1'>Conserved Residues</scene> | ||
=References= | =References= | ||
<references/> | <references/> | ||
| - | [http://www.wikipedia.org E.ColiBranchingEnzyme] | + | <ref name="1m7x">[http://www.wikipedia.org E.ColiBranchingEnzyme] |
Revision as of 17:19, 4 April 2011
| This Sandbox is Reserved from January 10, 2010, through April 10, 2011 for use in BCMB 307-Proteins course taught by Andrea Gorrell at the University of Northern British Columbia, Prince George, BC, Canada. |
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Introduction
[1] [1] Escherichia coli Branching Enzyme (BE) (1,4-a-glucan 6-glucosyltransferase)catalyzes the formation of a-1,6 branch points of glycogen [2]
