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New page: left|200px<br /><applet load="1u9j" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u9j, resolution 2.40Å" /> '''Crystal Structure of...
 
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[[Image:1u9j.gif|left|200px]]<br /><applet load="1u9j" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1u9j, resolution 2.40&Aring;" />
'''Crystal Structure of E. coli ArnA (PmrI) Decarboxylase Domain'''<br />


==Overview==
==Crystal Structure of E. coli ArnA (PmrI) Decarboxylase Domain==
Gram-negative bacteria including Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa can modify the structure of lipid A in their, outer membrane with 4-amino-4-deoxy-l-arabinose (Ara4N). Such modification, results in resistance to cationic antimicrobial peptides of the innate, immune system and antibiotics such as polymyxin. ArnA is a key enzyme in, the lipid A modification pathway, and its deletion abolishes both the, Ara4N-lipid A modification and polymyxin resistance. ArnA is a, bifunctional enzyme. It can catalyze (i) the NAD(+)-dependent, decarboxylation of UDP-glucuronic acid to UDP-4-keto-arabinose and (ii), the N-10-formyltetrahydrofolate-dependent formylation of, UDP-4-amino-4-deoxy-l-arabinose. We show that the NAD(+)-dependent, decarboxylating activity is contained in the 360 amino acid C-terminal, domain of ArnA. This domain is separable from the N-terminal fragment, and, its activity is identical to that of the full-length enzyme. The crystal, structure of the ArnA decarboxylase domain from E. coli is presented here., The structure confirms that the enzyme belongs to the short-chain, dehydrogenase/reductase (SDR) family. On the basis of sequence and, structure comparisons of the ArnA decarboxylase domain with other members, of the short-chain dehydrogenase/reductase (SDR) family, we propose a, binding model for NAD(+) and UDP-glucuronic acid and the involvement of, residues T(432), Y(463), K(467), R(619), and S(433) in the mechanism of, NAD(+)-dependent oxidation of the 4''-OH of the UDP-glucuronic acid and, decarboxylation of the UDP-4-keto-glucuronic acid intermediate.
<StructureSection load='1u9j' size='340' side='right'caption='[[1u9j]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1u9j]] is a 1 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=1U9J OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1U9J 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=SO4:SULFATE+ION'>SO4</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=1u9j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1u9j OCA], [https://pdbe.org/1u9j PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1u9j RCSB], [https://www.ebi.ac.uk/pdbsum/1u9j PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1u9j ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ARNA_ECOLI ARNA_ECOLI] Bifunctional enzyme that catalyzes the oxidative decarboxylation of UDP-glucuronic acid (UDP-GlcUA) to UDP-4-keto-arabinose (UDP-Ara4O) and the addition of a formyl group to UDP-4-amino-4-deoxy-L-arabinose (UDP-L-Ara4N) to form UDP-L-4-formamido-arabinose (UDP-L-Ara4FN). The modified arabinose is attached to lipid A and is required for resistance to polymyxin and cationic antimicrobial peptides.<ref>PMID:11706007</ref> <ref>PMID:15695810</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/u9/1u9j_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=1u9j ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Gram-negative bacteria including Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa can modify the structure of lipid A in their outer membrane with 4-amino-4-deoxy-l-arabinose (Ara4N). Such modification results in resistance to cationic antimicrobial peptides of the innate immune system and antibiotics such as polymyxin. ArnA is a key enzyme in the lipid A modification pathway, and its deletion abolishes both the Ara4N-lipid A modification and polymyxin resistance. ArnA is a bifunctional enzyme. It can catalyze (i) the NAD(+)-dependent decarboxylation of UDP-glucuronic acid to UDP-4-keto-arabinose and (ii) the N-10-formyltetrahydrofolate-dependent formylation of UDP-4-amino-4-deoxy-l-arabinose. We show that the NAD(+)-dependent decarboxylating activity is contained in the 360 amino acid C-terminal domain of ArnA. This domain is separable from the N-terminal fragment, and its activity is identical to that of the full-length enzyme. The crystal structure of the ArnA decarboxylase domain from E. coli is presented here. The structure confirms that the enzyme belongs to the short-chain dehydrogenase/reductase (SDR) family. On the basis of sequence and structure comparisons of the ArnA decarboxylase domain with other members of the short-chain dehydrogenase/reductase (SDR) family, we propose a binding model for NAD(+) and UDP-glucuronic acid and the involvement of residues T(432), Y(463), K(467), R(619), and S(433) in the mechanism of NAD(+)-dependent oxidation of the 4''-OH of the UDP-glucuronic acid and decarboxylation of the UDP-4-keto-glucuronic acid intermediate.


==About this Structure==
Crystal structure of Escherichia coli ArnA (PmrI) decarboxylase domain. A key enzyme for lipid A modification with 4-amino-4-deoxy-L-arabinose and polymyxin resistance.,Gatzeva-Topalova PZ, May AP, Sousa MC Biochemistry. 2004 Oct 26;43(42):13370-9. PMID:15491143<ref>PMID:15491143</ref>
1U9J is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1U9J OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Crystal structure of Escherichia coli ArnA (PmrI) decarboxylase domain. A key enzyme for lipid A modification with 4-amino-4-deoxy-L-arabinose and polymyxin resistance., Gatzeva-Topalova PZ, May AP, Sousa MC, Biochemistry. 2004 Oct 26;43(42):13370-9. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15491143 15491143]
</div>
<div class="pdbe-citations 1u9j" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Gatzeva-Topalova, P.Z.]]
[[Category: Gatzeva-Topalova PZ]]
[[Category: May, A.P.]]
[[Category: May AP]]
[[Category: Sousa, M.C.]]
[[Category: Sousa MC]]
[[Category: SO4]]
[[Category: decarboxylase; x-ray structure; e.coli proteome]]
 
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