1h4j
From Proteopedia
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| - | [[Image:1h4j.gif|left|200px]]<br /> | + | [[Image:1h4j.gif|left|200px]]<br /><applet load="1h4j" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1h4j" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1h4j, resolution 3.0Å" /> | caption="1h4j, resolution 3.0Å" /> | ||
'''METHYLOBACTERIUM EXTORQUENS METHANOL DEHYDROGENASE D303E MUTANT'''<br /> | '''METHYLOBACTERIUM EXTORQUENS METHANOL DEHYDROGENASE D303E MUTANT'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1H4J is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Methylobacterium_extorquens Methylobacterium extorquens] with CA and PQQ as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alcohol_dehydrogenase_(acceptor) Alcohol dehydrogenase (acceptor)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.99.8 1.1.99.8] | + | 1H4J is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Methylobacterium_extorquens Methylobacterium extorquens] with CA and PQQ as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alcohol_dehydrogenase_(acceptor) Alcohol dehydrogenase (acceptor)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.99.8 1.1.99.8] Known structural/functional Sites: <scene name='pdbsite=AC1:Pqq Binding Site For Chain A'>AC1</scene>, <scene name='pdbsite=AC2:Ca Binding Site For Chain A'>AC2</scene>, <scene name='pdbsite=AC3:Pqq Binding Site For Chain C'>AC3</scene>, <scene name='pdbsite=AC5:Pqq Binding Site For Chain E'>AC5</scene>, <scene name='pdbsite=AC6:Ca Binding Site For Chain E'>AC6</scene>, <scene name='pdbsite=AC7:Pqq Binding Site For Chain G'>AC7</scene> and <scene name='pdbsite=AC8:Ca Binding Site For Chain G'>AC8</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1H4J OCA]. |
==Reference== | ==Reference== | ||
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[[Category: quinoprotein]] | [[Category: quinoprotein]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 15:58:41 2007'' |
Revision as of 13:48, 18 December 2007
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METHYLOBACTERIUM EXTORQUENS METHANOL DEHYDROGENASE D303E MUTANT
Overview
Two proteins specifically involved in methanol oxidation in the, methylotrophic bacterium Methylobacterium extorquens have been modified by, site-directed mutagenesis. Mutation of the proposed active site base, (Asp303) to glutamate in methanol dehydrogenase (MDH) gave an active, enzyme (D303E-MDH) with a greatly reduced affinity for substrate and with, a lower activation energy. Results of kinetic and deuterium isotope, studies showed that the essential mechanism in the mutant protein was, unchanged, and that the step requiring activation by ammonia remained rate, limiting. No spectrally detectable intermediates could be observed during, the reaction. The X-ray structure, determined to 3 A resolution, of, D303E-MDH showed that the position and coordination geometry of the Ca2+, ion in the active site was altered; the larger Glu303 side chain was, coordinated to the Ca2+ ion and also hydrogen bonded to the O5 atom of, pyrroloquinoline quinone (PQQ). The properties and structure of the, D303E-MDH are consistent with the previous proposal that the reaction in, MDH is initiated by proton abstraction involving Asp303, and that the, mechanism involves a direct hydride transfer reaction. Mutation of the two, adjacent cysteine residues that make up the novel disulfide ring in the, active site of MDH led to an inactive enzyme, confirming the essential, role of this remarkable ring structure. Mutations of cytochrome c(L), which is the electron acceptor from MDH was used to identify Met109 as the, sixth ligand to the heme.
About this Structure
1H4J is a Protein complex structure of sequences from Methylobacterium extorquens with CA and PQQ as ligands. Active as Alcohol dehydrogenase (acceptor), with EC number 1.1.99.8 Known structural/functional Sites: , , , , , and . Full crystallographic information is available from OCA.
Reference
Site-directed mutagenesis and X-ray crystallography of the PQQ-containing quinoprotein methanol dehydrogenase and its electron acceptor, cytochrome c(L)., Afolabi PR, Mohammed F, Amaratunga K, Majekodunmi O, Dales SL, Gill R, Thompson D, Cooper JB, Wood SP, Goodwin PM, Anthony C, Biochemistry. 2001 Aug 21;40(33):9799-809. PMID:11502173
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