1iqx: Difference between revisions
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[[Image: | ==CRYSTAL STRUCTURE OF COBALT-SUBSTITUTED AMINE OXIDASE FROM ARTHROBACTER GLOBIFORMIS== | ||
<StructureSection load='1iqx' size='340' side='right' caption='[[1iqx]], [[Resolution|resolution]] 2.00Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1iqx]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Arthrobacter_globiformis Arthrobacter globiformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IQX OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1IQX FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CO:COBALT+(II)+ION'>CO</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=TPQ:5-(2-CARBOXY-2-AMINOETHYL)-2-HYDROXY-1,4-BENZOQUINONE'>TPQ</scene></td></tr> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1av4|1av4]], [[1avl|1avl]], [[1avk|1avk]], [[1iqy|1iqy]]</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Oxidoreductase Oxidoreductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.4.3.21 and 1.4.3.22 1.4.3.21 and 1.4.3.22] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1iqx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iqx OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1iqx RCSB], [http://www.ebi.ac.uk/pdbsum/1iqx PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/iq/1iqx_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The role of the active site Cu(2+) of phenylethylamine oxidase from Arthrobacter globiformis (AGAO) has been studied by substitution with other divalent cations, where we were able to remove >99.5% of Cu(2+) from the active site. The enzymes reconstituted with Co(2+) and Ni(2+) (Co- and Ni-AGAO) exhibited 2.2 and 0.9% activities, respectively, of the original Cu(2+)-enzyme (Cu-AGAO), but their K(m) values for amine substrate and dioxygen were comparable. X-ray crystal structures of the Co- and Ni-AGAO were solved at 2.0-1.8 A resolution. These structures revealed changes in the metal coordination environment when compared to that of Cu-AGAO. However, the hydrogen-bonding network around the active site involving metal-coordinating and noncoordinating water molecules was preserved. Upon anaerobic mixing of the Cu-, Co-, and Ni-AGAO with amine substrate, the 480 nm absorption band characteristic of the oxidized form of the topaquinone cofactor (TPQ(ox)) disappeared rapidly (< 6 ms), yielding the aminoresorcinol form of the reduced cofactor (TPQ(amr)). In contrast to the substrate-reduced Cu-AGAO, the semiquinone radical (TPQ(sq)) was not detected in Co- and Ni-AGAO. Further, in the latter, TPQ(amr) reacted reversibly with the product aldehyde to form a species with a lambda(max) at around 350 nm that was assigned as the neutral form of the product Schiff base (TPQ(pim)). Introduction of dioxygen to the substrate-reduced Co- and Ni-AGAO resulted in the formation of a TPQ-related intermediate absorbing at around 360 nm, which was assigned to the neutral iminoquinone form of the 2e(-)-oxidized cofactor (TPQ(imq)) and which decayed concomitantly with the generation of TPQ(ox). The rate of TPQ(imq) formation and its subsequent decay in Co- and Ni-AGAO was slow when compared to those of the corresponding reactions in Cu-AGAO. The low catalytic activities of the metal-substituted enzymes are due to the impaired efficiencies of the oxidative half-reaction in the catalytic cycle of amine oxidation. On the basis of these results, we propose that the native Cu(2+) ion has essential roles such as catalyzing the electron transfer between TPQ(amr) and dioxygen, in part by providing a binding site for 1e(-)- and 2e(-)-reduced dioxygen species to be efficiently protonated and released and also preventing the back reaction between the product aldehyde and TPQ(amr). | |||
Role of copper ion in bacterial copper amine oxidase: spectroscopic and crystallographic studies of metal-substituted enzymes.,Kishishita S, Okajima T, Kim M, Yamaguchi H, Hirota S, Suzuki S, Kuroda S, Tanizawa K, Mure M J Am Chem Soc. 2003 Jan 29;125(4):1041-55. PMID:12537504<ref>PMID:12537504</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Arthrobacter globiformis]] | [[Category: Arthrobacter globiformis]] | ||
[[Category: Oxidoreductase]] | [[Category: Oxidoreductase]] | ||