View source for 7kj9


==Wild-type epi-isozizaene synthase: complex with 3 Mg2+ and risedronate==
<StructureSection load='7kj9' size='340' side='right'caption='[[7kj9]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7kj9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_coelicolor Streptomyces coelicolor]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7KJ9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7KJ9 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=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=RIS:1-HYDROXY-2-(3-PYRIDINYL)ETHYLIDENE+BIS-PHOSPHONIC+ACID'>RIS</scene>, <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=7kj9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7kj9 OCA], [https://pdbe.org/7kj9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7kj9 RCSB], [https://www.ebi.ac.uk/pdbsum/7kj9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7kj9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CYC1_STRCO CYC1_STRCO] Catalyzes the cyclization of farnesyl diphosphate (FPP) to the sesquiterpene epi-isozizaene.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The sesquiterpene cyclase epi-isozizaene synthase (EIZS) catalyzes the cyclization of farnesyl diphosphate to form the tricyclic precursor of the antibiotic albaflavenone. The hydrophobic active site is largely defined by aromatic residues that direct a multistep reaction sequence through multiple carbocation intermediates. The previous substitution of polar residues for a key aromatic residue, F96, converts EIZS into a high-fidelity sesquisabinene synthase: the F96S, F96M, and F96Q variants generate 78%, 91%, and 97% sesquisabinene A, respectively. Here, we report high-resolution X-ray crystal structures of two of these reprogrammed cyclases. The structures of the F96M EIZS-Mg(2+)3-risedronate and F96M EIZS-Mg(2+)3-inorganic pyrophosphate-benzyltriethylammonium cation complexes reveal structural changes in the F96 aromatic cluster that redirect the cyclization pathway leading from the bisabolyl carbocation intermediate in catalysis. The structure of the F96S EIZS-Mg(2+)3-neridronate complex reveals a partially occupied inhibitor and an enzyme active site caught in transition between open and closed states. Finally, three structures of wild-type EIZS complexed with the bisphosphonate inhibitors neridronate, pamidronate, and risedronate provide a foundation for understanding binding differences between wild-type and variant enzymes. These structures provide new insight regarding active site flexibility, particularly with regard to the potential for subtle expansion and contraction to accommodate ligands of varying sizes as well as bound water molecules. Additionally, these structures highlight the importance of conformational changes in the F96 aromatic cluster that could influence cation-pi interactions with carbocation intermediates in catalysis.

An Aromatic Cluster in the Active Site of epi-Isozizaene Synthase Is an Electrostatic Toggle for Divergent Terpene Cyclization Pathways.,Ronnebaum TA, Gardner SM, Christianson DW Biochemistry. 2020 Dec 3. doi: 10.1021/acs.biochem.0c00876. PMID:33270439<ref>PMID:33270439</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7kj9" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Streptomyces coelicolor]]
[[Category: Christianson DW]]
[[Category: Gardner SM]]
[[Category: Ronnebaum TA]]