View source for 1f91


==BETA-KETOACYL-[ACYL-CARRIER-PROTEIN] SYNTHASE I IN COMPLEX WITH C10 FATTY ACID SUBSTRATE==
<StructureSection load='1f91' size='340' side='right'caption='[[1f91]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1f91]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F91 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1F91 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]] 2.4&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DKA:DECANOIC+ACID'>DKA</scene>, <scene name='pdbligand=OH:HYDROXIDE+ION'>OH</scene></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=1f91 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f91 OCA], [https://pdbe.org/1f91 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1f91 RCSB], [https://www.ebi.ac.uk/pdbsum/1f91 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1f91 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/FABB_ECOLI FABB_ECOLI] Catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP. Specific for elongation from C-10 to unsaturated C-16 and C-18 fatty acids.
== 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/f9/1f91_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1f91 ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: beta-ketoacyl-acyl carrier protein synthase (KAS) I is vital for the construction of the unsaturated fatty acid carbon skeletons characterizing E. coli membrane lipids. The new carbon-carbon bonds are created by KAS I in a Claisen condensation performed in a three-step enzymatic reaction. KAS I belongs to the thiolase fold enzymes, of which structures are known for five other enzymes. RESULTS: Structures of the catalytic Cys-Ser KAS I mutant with covalently bound C10 and C12 acyl substrates have been determined to 2.40 and 1.85 A resolution, respectively. The KAS I dimer is not changed by the formation of the complexes but reveals an asymmetric binding of the two substrates bound to the dimer. A detailed model is proposed for the catalysis of KAS I. Of the two histidines required for decarboxylation, one donates a hydrogen bond to the malonyl thioester oxo group, and the other abstracts a proton from the leaving group. CONCLUSIONS: The same mechanism is proposed for KAS II, which also has a Cys-His-His active site triad. Comparison to the active site architectures of other thiolase fold enzymes carrying out a decarboxylation step suggests that chalcone synthase and KAS III with Cys-His-Asn triads use another mechanism in which both the histidine and the asparagine interact with the thioester oxo group. The acyl binding pockets of KAS I and KAS II are so similar that they alone cannot provide the basis for their differences in substrate specificity.

Structures of beta-ketoacyl-acyl carrier protein synthase I complexed with fatty acids elucidate its catalytic machinery.,Olsen JG, Kadziola A, von Wettstein-Knowles P, Siggaard-Andersen M, Larsen S Structure. 2001 Mar 7;9(3):233-43. PMID:11286890<ref>PMID:11286890</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1f91" style="background-color:#fffaf0;"></div>

==See Also==
*[[Acyl carrier protein synthase 3D structures|Acyl carrier protein synthase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Kadziola A]]
[[Category: Larsen S]]
[[Category: Olsen JG]]
[[Category: Siggaard-Andersen M]]
[[Category: Wettstein-Knowles PV]]