1ah5
From Proteopedia
(New page: 200px<br /><applet load="1ah5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ah5, resolution 2.4Å" /> '''REDUCED FORM SELENOME...) |
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| - | [[Image:1ah5.gif|left|200px]]<br /><applet load="1ah5" size=" | + | [[Image:1ah5.gif|left|200px]]<br /><applet load="1ah5" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ah5, resolution 2.4Å" /> | caption="1ah5, resolution 2.4Å" /> | ||
'''REDUCED FORM SELENOMETHIONINE-LABELLED HYDROXYMETHYLBILANE SYNTHASE DETERMINED BY MAD'''<br /> | '''REDUCED FORM SELENOMETHIONINE-LABELLED HYDROXYMETHYLBILANE SYNTHASE DETERMINED BY MAD'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The enzyme hydroxymethylbilane synthase (HMBS, E.C. 4.3.1.8) catalyzes the | + | The enzyme hydroxymethylbilane synthase (HMBS, E.C. 4.3.1.8) catalyzes the conversion of porphobilinogen into hydroxymethylbilane, a key intermediate for the biosynthesis of heme, chlorophylls, vitamin B12 and related macrocycles. The enzyme is found in all organisms, except viruses. The crystal structure of the selenomethionine-labelled enzyme ([SeMet]HMBS) from Escherichia coli has been solved by the multi-wavelength anomalous dispersion (MAD) experimental method using the Daresbury SRS station 9.5. In addition, [SeMet]HMBS has been studied by MAD at the Grenoble ESRF MAD beamline BM14 (BL19) and this work is described especially with respect to the use of the ESRF CCD detector. The structure at ambient temperature has been refined, the R factor being 16.8% at 2. 4 A resolution. The dipyrromethane cofactor of the enzyme is preserved in its reduced form in the crystal and its geometrical shape is in full agreement with the crystal structures of authentic dipyrromethanes. Proximal to the reactive C atom of the reduced cofactor, spherical density is seen consistent with there being a water molecule ideally placed to take part in the final step of the enzyme reaction cycle. Intriguingly, the loop with residues 47-58 is not ordered in the structure of this form of the enzyme, which carries no substrate. Direct experimental study of the active enzyme is now feasible using time-resolved Laue diffraction and freeze-trapping, building on the structural work described here as the foundation. |
==About this Structure== | ==About this Structure== | ||
| - | 1AH5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with DPM as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Hydroxymethylbilane_synthase Hydroxymethylbilane synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.61 2.5.1.61] Full crystallographic information is available from [http:// | + | 1AH5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=DPM:'>DPM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Hydroxymethylbilane_synthase Hydroxymethylbilane synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.61 2.5.1.61] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AH5 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Cassetta, A.]] | [[Category: Cassetta, A.]] | ||
| - | [[Category: Harrop, S | + | [[Category: Harrop, S J.]] |
| - | [[Category: Helliwell, J | + | [[Category: Helliwell, J R.]] |
| - | [[Category: Nieh, Y | + | [[Category: Nieh, Y P.]] |
[[Category: DPM]] | [[Category: DPM]] | ||
[[Category: all alpha/beta]] | [[Category: all alpha/beta]] | ||
| Line 23: | Line 23: | ||
[[Category: lyase]] | [[Category: lyase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:44:27 2008'' |
Revision as of 09:44, 21 February 2008
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REDUCED FORM SELENOMETHIONINE-LABELLED HYDROXYMETHYLBILANE SYNTHASE DETERMINED BY MAD
Overview
The enzyme hydroxymethylbilane synthase (HMBS, E.C. 4.3.1.8) catalyzes the conversion of porphobilinogen into hydroxymethylbilane, a key intermediate for the biosynthesis of heme, chlorophylls, vitamin B12 and related macrocycles. The enzyme is found in all organisms, except viruses. The crystal structure of the selenomethionine-labelled enzyme ([SeMet]HMBS) from Escherichia coli has been solved by the multi-wavelength anomalous dispersion (MAD) experimental method using the Daresbury SRS station 9.5. In addition, [SeMet]HMBS has been studied by MAD at the Grenoble ESRF MAD beamline BM14 (BL19) and this work is described especially with respect to the use of the ESRF CCD detector. The structure at ambient temperature has been refined, the R factor being 16.8% at 2. 4 A resolution. The dipyrromethane cofactor of the enzyme is preserved in its reduced form in the crystal and its geometrical shape is in full agreement with the crystal structures of authentic dipyrromethanes. Proximal to the reactive C atom of the reduced cofactor, spherical density is seen consistent with there being a water molecule ideally placed to take part in the final step of the enzyme reaction cycle. Intriguingly, the loop with residues 47-58 is not ordered in the structure of this form of the enzyme, which carries no substrate. Direct experimental study of the active enzyme is now feasible using time-resolved Laue diffraction and freeze-trapping, building on the structural work described here as the foundation.
About this Structure
1AH5 is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Hydroxymethylbilane synthase, with EC number 2.5.1.61 Full crystallographic information is available from OCA.
Reference
Determination of the structure of seleno-methionine-labelled hydroxymethylbilane synthase in its active form by multi-wavelength anomalous dispersion., Hadener A, Matzinger PK, Battersby AR, McSweeney S, Thompson AW, Hammersley AP, Harrop SJ, Cassetta A, Deacon A, Hunter WN, Nieh YP, Raftery J, Hunter N, Helliwell JR, Acta Crystallogr D Biol Crystallogr. 1999 Mar;55(Pt 3):631-43. PMID:10089459
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