1b80
From Proteopedia
(New page: 200px<br /><applet load="1b80" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b80, resolution 1.73Å" /> '''REC. LIGNIN PEROXIDA...) |
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| - | [[Image:1b80.gif|left|200px]]<br /><applet load="1b80" size=" | + | [[Image:1b80.gif|left|200px]]<br /><applet load="1b80" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1b80, resolution 1.73Å" /> | caption="1b80, resolution 1.73Å" /> | ||
'''REC. LIGNIN PEROXIDASE H8 OXIDATIVELY PROCESSED'''<br /> | '''REC. LIGNIN PEROXIDASE H8 OXIDATIVELY PROCESSED'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The heme enzyme lignin peroxidase (LiP) from the white rot fungus | + | The heme enzyme lignin peroxidase (LiP) from the white rot fungus Phanerochaete chrysosporium contains a solvent exposed redox active tryptophan residue (Trp171) that carries a unique hydroxy group stereo-specifically attached to its C(beta) atom. A Trp171Phe mutant has no activity at all towards the substrate veratryl alcohol. The mechanism of veratryl alcohol oxidation involving beta-hydroxy-Trp171 is largely unknown. Here, we present the first crystal structures of LiP isozyme H8 at high resolution in its pristine non-hydroxylated form, of the C(beta)-hydroxylated form, and of the Trp171Phe mutant using recombinantly expressed and refolded protein produced from Escherichia coli. As a consequence, all structures are unglycosylated. Structural changes in response to the mutation are marginal and allow us to attribute the complete lack of activity exclusively to the absence of the redox active indole side-chain. The origin of the stereospecificity of the Trp171 hydroxylation can be explained on structural grounds. A reaction mechanism involving Trp171 is proposed and the possible function of the modification is discussed. Another important result regarding the ongoing debate on the co-ordination state of the heme iron in the resting state is that the iron is six co-ordinate in all cases the data being collected at room temperature. The mean distance from the iron to the distal water ligand is 2.18(+/-0.08) A. The radical scavenger orcinol was found to decrease radiation damage to the crystals, during data collection at room temperature. |
==About this Structure== | ==About this Structure== | ||
| - | 1B80 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phanerochaete_chrysosporium Phanerochaete chrysosporium] with CA and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Lignin_peroxidase Lignin peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.14 1.11.1.14] Full crystallographic information is available from [http:// | + | 1B80 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Phanerochaete_chrysosporium Phanerochaete chrysosporium] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Lignin_peroxidase Lignin peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.14 1.11.1.14] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B80 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Blodig, W.]] | [[Category: Blodig, W.]] | ||
| - | [[Category: Doyle, W | + | [[Category: Doyle, W A.]] |
[[Category: Piontek, K.]] | [[Category: Piontek, K.]] | ||
| - | [[Category: Smith, A | + | [[Category: Smith, A T.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: HEM]] | [[Category: HEM]] | ||
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[[Category: radical reaction]] | [[Category: radical reaction]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:30 2008'' |
Revision as of 09:52, 21 February 2008
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REC. LIGNIN PEROXIDASE H8 OXIDATIVELY PROCESSED
Overview
The heme enzyme lignin peroxidase (LiP) from the white rot fungus Phanerochaete chrysosporium contains a solvent exposed redox active tryptophan residue (Trp171) that carries a unique hydroxy group stereo-specifically attached to its C(beta) atom. A Trp171Phe mutant has no activity at all towards the substrate veratryl alcohol. The mechanism of veratryl alcohol oxidation involving beta-hydroxy-Trp171 is largely unknown. Here, we present the first crystal structures of LiP isozyme H8 at high resolution in its pristine non-hydroxylated form, of the C(beta)-hydroxylated form, and of the Trp171Phe mutant using recombinantly expressed and refolded protein produced from Escherichia coli. As a consequence, all structures are unglycosylated. Structural changes in response to the mutation are marginal and allow us to attribute the complete lack of activity exclusively to the absence of the redox active indole side-chain. The origin of the stereospecificity of the Trp171 hydroxylation can be explained on structural grounds. A reaction mechanism involving Trp171 is proposed and the possible function of the modification is discussed. Another important result regarding the ongoing debate on the co-ordination state of the heme iron in the resting state is that the iron is six co-ordinate in all cases the data being collected at room temperature. The mean distance from the iron to the distal water ligand is 2.18(+/-0.08) A. The radical scavenger orcinol was found to decrease radiation damage to the crystals, during data collection at room temperature.
About this Structure
1B80 is a Single protein structure of sequence from Phanerochaete chrysosporium with and as ligands. Active as Lignin peroxidase, with EC number 1.11.1.14 Full crystallographic information is available from OCA.
Reference
Crystal structures of pristine and oxidatively processed lignin peroxidase expressed in Escherichia coli and of the W171F variant that eliminates the redox active tryptophan 171. Implications for the reaction mechanism., Blodig W, Smith AT, Doyle WA, Piontek K, J Mol Biol. 2001 Jan 26;305(4):851-61. PMID:11162097
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