2aj9: Difference between revisions
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==X-ray crystal structure of W42A,R161A double mutant of Mycobacterium tuberculosis beta-ketoacyl-ACP synthase III== | |||
<StructureSection load='2aj9' size='340' side='right'caption='[[2aj9]], [[Resolution|resolution]] 2.50Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2aj9]] 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=2AJ9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2AJ9 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]] 2.5Å</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=2aj9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2aj9 OCA], [https://pdbe.org/2aj9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2aj9 RCSB], [https://www.ebi.ac.uk/pdbsum/2aj9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2aj9 ProSAT], [https://www.topsan.org/Proteins/TBSGC/2aj9 TOPSAN]</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/aj/2aj9_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=2aj9 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
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). | |||
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:16040614<ref>PMID:16040614</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 2aj9" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Acyl carrier protein synthase 3D structures|Acyl carrier protein synthase 3D structures]] | |||
[[Category: | == References == | ||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Mycobacterium tuberculosis]] | [[Category: Mycobacterium tuberculosis]] | ||
[[Category: Besra GS]] | |||
[[Category: Besra | [[Category: Brown AK]] | ||
[[Category: Brown | [[Category: Dover LG]] | ||
[[Category: Dover | [[Category: Kremer L]] | ||
[[Category: Kremer | [[Category: Lindenberg S]] | ||
[[Category: Lindenberg | [[Category: Sacchettini JC]] | ||
[[Category: Sacchettini | [[Category: Sridharan S]] | ||
[[Category: Sridharan | |||