2pbg
From Proteopedia
(New page: 200px<br /><applet load="2pbg" size="450" color="white" frame="true" align="right" spinBox="true" caption="2pbg, resolution 2.50Å" /> '''6-PHOSPHO-BETA-D-GAL...) |
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| - | [[Image:2pbg.jpg|left|200px]]<br /><applet load="2pbg" size=" | + | [[Image:2pbg.jpg|left|200px]]<br /><applet load="2pbg" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2pbg, resolution 2.50Å" /> | caption="2pbg, resolution 2.50Å" /> | ||
'''6-PHOSPHO-BETA-D-GALACTOSIDASE FORM-B'''<br /> | '''6-PHOSPHO-BETA-D-GALACTOSIDASE FORM-B'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The initial structural model of 6-phospho-beta-galactosidase from | + | The initial structural model of 6-phospho-beta-galactosidase from Lactococcus lactis was refined to an R-factor of 16.4% (R[free] = 23.6%) to 2.3 A resolution (1 A = 0.1 nm), and the structures of three other crystal forms were solved by molecular replacement. The four structural models are essentially identical. The catalytic center of the enzyme is approximately at the mass center of the molecule and can only be reached through a 20 A long channel, which is observed with an "open" or "closed" entrance. The closed entrance is probably too small for the educt lactose-6-phosphate to enter, but large enough for the first product glucose to leave. Among the presented structures is a complex between an almost inactive mutant and the second product galactose-6-phosphate, which is exclusively bound at side-chains. A superposition (onto the native enzyme) of galactose-6-phosphate as bound to the mutant suggests the geometry of a postulated covalent intermediate. The binding mode of the educt was modeled, starting from the bound galactose-6-phosphate. A tightly fixed tryptophan is used as a chopping-board for splitting the disaccharide, and several other aromatic residues in the active center cavity are likely to participate in substrate transport/binding. |
==About this Structure== | ==About this Structure== | ||
| - | 2PBG 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 SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/6-phospho-beta-galactosidase 6-phospho-beta-galactosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.85 3.2.1.85] Full crystallographic information is available from [http:// | + | 2PBG 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=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/6-phospho-beta-galactosidase 6-phospho-beta-galactosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.85 3.2.1.85] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PBG OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Lactococcus lactis]] | [[Category: Lactococcus lactis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Schulz, G | + | [[Category: Schulz, G E.]] |
[[Category: Wiesmann, C.]] | [[Category: Wiesmann, C.]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:27:55 2008'' |
Revision as of 16:27, 21 February 2008
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6-PHOSPHO-BETA-D-GALACTOSIDASE FORM-B
Overview
The initial structural model of 6-phospho-beta-galactosidase from Lactococcus lactis was refined to an R-factor of 16.4% (R[free] = 23.6%) to 2.3 A resolution (1 A = 0.1 nm), and the structures of three other crystal forms were solved by molecular replacement. The four structural models are essentially identical. The catalytic center of the enzyme is approximately at the mass center of the molecule and can only be reached through a 20 A long channel, which is observed with an "open" or "closed" entrance. The closed entrance is probably too small for the educt lactose-6-phosphate to enter, but large enough for the first product glucose to leave. Among the presented structures is a complex between an almost inactive mutant and the second product galactose-6-phosphate, which is exclusively bound at side-chains. A superposition (onto the native enzyme) of galactose-6-phosphate as bound to the mutant suggests the geometry of a postulated covalent intermediate. The binding mode of the educt was modeled, starting from the bound galactose-6-phosphate. A tightly fixed tryptophan is used as a chopping-board for splitting the disaccharide, and several other aromatic residues in the active center cavity are likely to participate in substrate transport/binding.
About this Structure
2PBG is a Single protein structure of sequence from Lactococcus lactis with as ligand. Active as 6-phospho-beta-galactosidase, with EC number 3.2.1.85 Full crystallographic information is available from OCA.
Reference
Crystal structures and mechanism of 6-phospho-beta-galactosidase from Lactococcus lactis., Wiesmann C, Hengstenberg W, Schulz GE, J Mol Biol. 1997 Jun 27;269(5):851-60. PMID:9223646
Page seeded by OCA on Thu Feb 21 18:27:55 2008
