View source for 5kik


==CmlA beta-hydroxylase in chemically reduced diferrous state==
<StructureSection load='5kik' size='340' side='right'caption='[[5kik]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5kik]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_venezuelae_ATCC_10712 Streptomyces venezuelae ATCC 10712]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5KIK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5KIK 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</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=5kik FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5kik OCA], [https://pdbe.org/5kik PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5kik RCSB], [https://www.ebi.ac.uk/pdbsum/5kik PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5kik ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CMLA_STRVP CMLA_STRVP] Involved in chloramphenicol biosynthesis (PubMed:20713732). Catalyzes the beta-hydroxylation of 4-amino-L-phenylalanine (L-PAPA) covalently bound to CmlP to form L-p-aminophenylserine (PubMed:20713732).<ref>PMID:20713732</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The first step in the nonribosomal peptide synthetase (NRPS)-based biosynthesis of chloramphenicol is the beta-hydroxylation of the precursor l-p-aminophenylalanine (l-PAPA) catalyzed by the monooxygenase CmlA. The active site of CmlA contains a dinuclear iron cluster that is reduced to the diferrous state (WTR) to initiate O2 activation. However, rapid O2 activation occurs only when WTR is bound to CmlP, the NRPS to which l-PAPA is covalently attached. Here the X-ray crystal structure of WTR is reported, which is very similar to that of the as-isolated diferric enzyme in which the irons are coordinately saturated. X-ray absorption spectroscopy is used to investigate the WTR cluster ligand structure as well as the structures of WTR in complex with a functional CmlP variant (CmlPAT) with and without l-PAPA attached. It is found that formation of the active WTR:CmlPAT-l-PAPA complex converts at least one iron of the cluster from six- to five-coordinate by changing a bidentately bound amino acid carboxylate to monodentate on Fe1. The only bidentate carboxylate in the structure of WTR is E377. The crystal structure of the CmlA variant E377D shows only monodentate carboxylate coordination. Reduced E377D reacts rapidly with O2 in the presence or absence of CmlPAT-l-PAPA, showing loss of regulation. However, this variant fails to catalyze hydroxylation, suggesting that E377 has the dual role of coupling regulation of O2 reactivity with juxtaposition of the substrate and the reactive oxygen species. The carboxylate shift in response to substrate binding represents a novel regulatory strategy for oxygen activation in diiron oxygenases.

A Carboxylate Shift Regulates Dioxygen Activation by the Diiron Nonheme beta-Hydroxylase CmlA upon Binding of a Substrate-Loaded Nonribosomal Peptide Synthetase.,Jasniewski AJ, Knoot CJ, Lipscomb JD, Que L Jr Biochemistry. 2016 Oct 18;55(41):5818-5831. doi: 10.1021/acs.biochem.6b00834., Epub 2016 Oct 7. PMID:27668828<ref>PMID:27668828</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5kik" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Streptomyces venezuelae ATCC 10712]]
[[Category: Knoot CJ]]
[[Category: Lipscomb JD]]