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| [[Image:1m1m.gif|left|200px]]<br /><applet load="1m1m" size="350" color="white" frame="true" align="right" spinBox="true"
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| caption="1m1m, resolution 2.70Å" />
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| '''X-RAY CRYSTAL STRUCTURE OF MYCOBACTERIUM TUBERCULOSIS BETA-KETOACYL-ACYL CARRIER PROTEIN SYNTHASE III (MTFABH)'''<br />
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| ==Overview== | | ==X-RAY CRYSTAL STRUCTURE OF MYCOBACTERIUM TUBERCULOSIS BETA-KETOACYL-ACYL CARRIER PROTEIN SYNTHASE III (MTFABH)== |
| Mycolic acids are the dominant feature of the Mycobacterium tuberculosis, cell wall. These alpha-alkyl, beta-hydroxy fatty acids are formed by the, condensation of two fatty acids, a long meromycolic acid and a shorter, C(24)-C(26) fatty acid. The component fatty acids are produced via a, combination of type I and II fatty acid synthases (FAS) with FAS-I, products being elongated by FAS-II toward meromycolic acids. The, beta-ketoacyl-acyl carrier protein (ACP) synthase III encoded by mtfabH, (mtFabH) links FAS-I and FAS-II, catalyzing the condensation of, FAS-I-derived acyl-CoAs with malonyl-acyl carrier protein (ACP). The, acyl-CoA chain length specificity of mtFabH was assessed in vitro; the, enzyme extended longer, physiologically relevant acyl-CoA primers when, paired with AcpM, its natural partner, than with Escherichia coli ACP. The, ability of the enzyme to use E. coli ACP suggests that a similar mode of, binding is likely with both ACPs, yet it is clear that unique factors, inherent to AcpM modulate the substrate specificity of mtFabH. Mutation of, proposed key mtFabH residues was used to define their catalytic roles., Substitution of supposed acyl-CoA binding residues reduced transacylation, with double substitutions totally abrogating activity. Mutation of Arg(46), revealed its more critical role in malonyl-AcpM decarboxylation than in, the acyl-CoA binding role. Interestingly, this effect was suppressed, intragenically by Arg(161) --> Ala substitution. Our structural studies, suggested that His(258), previously implicated in malonyl-ACP, decarboxylation, also acts as an anchor point for a network of water, molecules that we propose promotes deprotonation and transacylation of, Cys(122).
| | <StructureSection load='1m1m' size='340' side='right'caption='[[1m1m]], [[Resolution|resolution]] 2.70Å' scene=''> |
| | == Structural highlights == |
| | <table><tr><td colspan='2'>[[1m1m]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycobacterium_tuberculosis Mycobacterium tuberculosis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M1M OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1M1M FirstGlance]. <br> |
| | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.7Å</td></tr> |
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1m1m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1m1m OCA], [https://pdbe.org/1m1m PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1m1m RCSB], [https://www.ebi.ac.uk/pdbsum/1m1m PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1m1m ProSAT]</span></td></tr> |
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/FABH_MYCTU FABH_MYCTU] Catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP. Catalyzes the first condensation reaction which initiates fatty acid synthesis and may therefore play a role in governing the total rate of fatty acid production. Possesses both acetoacetyl-ACP synthase and acetyl transacylase activities. Has some substrate specificity for long chain acyl-CoA such as myristoyl-CoA. Does not use acyl-CoA as primer. Its substrate specificity determines the biosynthesis of mycolic acid fatty acid chain, which is characteristic of mycobacterial cell wall.<ref>PMID:10840036</ref> |
| | == 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/m1/1m1m_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/main_output.php?pdb_ID=1m1m ConSurf]. |
| | <div style="clear:both"></div> |
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| ==About this Structure== | | ==See Also== |
| 1M1M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycobacterium_tuberculosis Mycobacterium tuberculosis]. Active as [http://en.wikipedia.org/wiki/Beta-ketoacyl-acyl-carrier-protein_synthase_I Beta-ketoacyl-acyl-carrier-protein synthase I], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.41 2.3.1.41] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M1M OCA].
| | *[[Acyl carrier protein synthase 3D structures|Acyl carrier protein synthase 3D structures]] |
| | | == References == |
| ==Reference== | | <references/> |
| Probing the mechanism of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III mtFabH: factors influencing catalysis and substrate specificity., Brown AK, Sridharan S, Kremer L, Lindenberg S, Dover LG, Sacchettini JC, Besra GS, J Biol Chem. 2005 Sep 16;280(37):32539-47. Epub 2005 Jul 22. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16040614 16040614]
| | __TOC__ |
| [[Category: Beta-ketoacyl-acyl-carrier-protein synthase I]] | | </StructureSection> |
| | [[Category: Large Structures]] |
| [[Category: Mycobacterium tuberculosis]] | | [[Category: Mycobacterium tuberculosis]] |
| [[Category: Single protein]]
| | [[Category: Sacchettini JC]] |
| [[Category: Sacchettini, J.C.]] | | [[Category: Sridharan S]] |
| [[Category: Sridharan, S.]] | |
| [[Category: TBSGC, TB.Structural.Genomics.Consortium.]]
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| [[Category: 3-oxoacyl-acyl carrier protein synthase iii]]
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| [[Category: alpha-beta-alpha-beta-alpha]]
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| [[Category: condensing enzyme]]
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| [[Category: mtfabh]]
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| [[Category: protein structure initiative]]
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| [[Category: psi]]
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| [[Category: structural genomics]]
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| [[Category: tb structural genomics consortium]]
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| [[Category: tbsgc]]
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| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 14:57:04 2008''
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