1j18

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[[Image:1j18.gif|left|200px]]<br /><applet load="1j18" size="350" color="white" frame="true" align="right" spinBox="true"
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[[Image:1j18.gif|left|200px]]
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caption="1j18, resolution 2.00&Aring;" />
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'''Crystal Structure of a Beta-Amylase from Bacillus cereus var. mycoides Cocrystallized with Maltose'''<br />
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{{Structure
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|PDB= 1j18 |SIZE=350|CAPTION= <scene name='initialview01'>1j18</scene>, resolution 2.00&Aring;
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|SITE=
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|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> and <scene name='pdbligand=ACY:ACETIC ACID'>ACY</scene>
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|ACTIVITY= [http://en.wikipedia.org/wiki/Beta-amylase Beta-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.2 3.2.1.2]
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|GENE=
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}}
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'''Crystal Structure of a Beta-Amylase from Bacillus cereus var. mycoides Cocrystallized with Maltose'''
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==Overview==
==Overview==
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==About this Structure==
==About this Structure==
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1J18 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_cereus Bacillus cereus] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=ACY:'>ACY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Beta-amylase Beta-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.2 3.2.1.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J18 OCA].
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1J18 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_cereus Bacillus cereus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J18 OCA].
==Reference==
==Reference==
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Crystal structure of a catalytic site mutant of beta-amylase from Bacillus cereus var. mycoides cocrystallized with maltopentaose., Miyake H, Kurisu G, Kusunoki M, Nishimura S, Kitamura S, Nitta Y, Biochemistry. 2003 May 20;42(19):5574-81. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12741813 12741813]
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Crystal structure of a catalytic site mutant of beta-amylase from Bacillus cereus var. mycoides cocrystallized with maltopentaose., Miyake H, Kurisu G, Kusunoki M, Nishimura S, Kitamura S, Nitta Y, Biochemistry. 2003 May 20;42(19):5574-81. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12741813 12741813]
[[Category: Bacillus cereus]]
[[Category: Bacillus cereus]]
[[Category: Beta-amylase]]
[[Category: Beta-amylase]]
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[[Category: tim barel]]
[[Category: tim barel]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:17:50 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:57:36 2008''

Revision as of 09:57, 20 March 2008

Image:1j18.gif


PDB ID 1j18

Drag the structure with the mouse to rotate
, resolution 2.00Å
Ligands: , and
Activity: Beta-amylase, with EC number 3.2.1.2
Coordinates: save as pdb, mmCIF, xml



Crystal Structure of a Beta-Amylase from Bacillus cereus var. mycoides Cocrystallized with Maltose


Overview

The X-ray crystal structure of a catalytic site mutant of beta-amylase, E172A (Glu172 --> Ala), from Bacillus cereus var. mycoides complexed with a substrate, maltopentaose (G5), and the wild-type enzyme complexed with maltose were determined at 2.1 and 2.0 A resolution, respectively. Clear and continuous density corresponding to G5 was observed in the active site of E172A, and thus, the substrate, G5, was not hydrolyzed. All glucose residues adopted a relaxed (4)C(1) conformation, and the conformation of the maltose unit for Glc2 and Glc3 was much different from those of other maltose units, where each glucose residue of G5 is named Glc1-Glc5 (Glc1 is at the nonreducing end). A water molecule was observed 3.3 A from the C1 atom of Glc2, and 3.0 A apart from the OE1 atom of Glu367 which acts as a general base. In the wild-type enzyme-maltose complex, two maltose molecules bind at subsites -2 and -1 and at subsites +1 and +2 in tandem. The conformation of the maltose molecules was similar to that of the condensation product of soybean beta-amylase, but differed from that of G5 in E172A. When the substrate flips between Glc2 and Glc3, the conformational energy of the maltose unit was calculated to be 20 kcal/mol higher than that of the cis conformation by MM3. We suggest that beta-amylase destabilizes the bond that is to be broken in the ES complex, decreasing the activation energy, DeltaG(++), which is the difference in free energy between this state and the transition state.

About this Structure

1J18 is a Single protein structure of sequence from Bacillus cereus. Full crystallographic information is available from OCA.

Reference

Crystal structure of a catalytic site mutant of beta-amylase from Bacillus cereus var. mycoides cocrystallized with maltopentaose., Miyake H, Kurisu G, Kusunoki M, Nishimura S, Kitamura S, Nitta Y, Biochemistry. 2003 May 20;42(19):5574-81. PMID:12741813

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