|
|
| Line 3: |
Line 3: |
| <StructureSection load='5zzd' size='340' side='right'caption='[[5zzd]], [[Resolution|resolution]] 1.85Å' scene=''> | | <StructureSection load='5zzd' size='340' side='right'caption='[[5zzd]], [[Resolution|resolution]] 1.85Å' scene=''> |
| == Structural highlights == | | == Structural highlights == |
| <table><tr><td colspan='2'>[[5zzd]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Aspfn Aspfn]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ZZD OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=5ZZD FirstGlance]. <br> | | <table><tr><td colspan='2'>[[5zzd]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Aspergillus_flavus_NRRL3357 Aspergillus flavus NRRL3357]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ZZD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5ZZD FirstGlance]. <br> |
| </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene></td></tr> | | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85Å</td></tr> |
| <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">lepI, AFLA_066940 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=332952 ASPFN])</td></tr> | | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAM:S-ADENOSYLMETHIONINE'>SAM</scene></td></tr> |
| <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=5zzd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5zzd OCA], [http://pdbe.org/5zzd PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5zzd RCSB], [http://www.ebi.ac.uk/pdbsum/5zzd PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5zzd ProSAT]</span></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=5zzd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5zzd OCA], [https://pdbe.org/5zzd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5zzd RCSB], [https://www.ebi.ac.uk/pdbsum/5zzd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5zzd ProSAT]</span></td></tr> |
| </table> | | </table> |
| == Function == | | == Function == |
| [[http://www.uniprot.org/uniprot/LEPI_ASPFN LEPI_ASPFN]] O-methyltransferase; part of the gene cluster 23 that mediates the biosynthesis of a family of 2-pyridones known as leporins (PubMed:20447271, PubMed:26051490). The hybrid PKS-NRPS synthetase lepA and the enoyl reductase lepG are responsible for fusion of phenylalanine with a hexaketide and subsequent release of the stable tetramic acid precursor, pre-leporin C (PubMed:26051490). Because lepA lacks a designated enoylreductase (ER) domain, the required activity is provided the enoyl reductase lepG (PubMed:26051490). It is possible that the dehydrogenase lepF also participates in production of pre-leporin C (PubMed:26051490). Cytochrome P450 monooxygenase lepH is then required for the ring expansion step to yield leporin C (PubMed:26051490). Leporin C is then presumably further oxidized by the N-hydroxylase lepD to form leporin B (PubMed:26051490). LepI may possess a function in biosynthesis upstream of lepA (PubMed:26051490). Leporin B is further oxidized in the presence of ferric ion to give the leporin B trimer-iron chelate, but whether or not this reaction is catalyzed by an enzyme in the pathway or by ferric ion is not determined yet (PubMed:26051490).<ref>PMID:26051490</ref> <ref>PMID:20447271</ref> | | [https://www.uniprot.org/uniprot/LEPI_ASPFN LEPI_ASPFN] O-methyltransferase; part of the gene cluster 23 that mediates the biosynthesis of a family of 2-pyridones known as leporins (PubMed:20447271, PubMed:26051490). The hybrid PKS-NRPS synthetase lepA and the enoyl reductase lepG are responsible for fusion of phenylalanine with a hexaketide and subsequent release of the stable tetramic acid precursor, pre-leporin C (PubMed:26051490). Because lepA lacks a designated enoylreductase (ER) domain, the required activity is provided the enoyl reductase lepG (PubMed:26051490). It is possible that the dehydrogenase lepF also participates in production of pre-leporin C (PubMed:26051490). Cytochrome P450 monooxygenase lepH is then required for the ring expansion step to yield leporin C (PubMed:26051490). Leporin C is then presumably further oxidized by the N-hydroxylase lepD to form leporin B (PubMed:26051490). LepI may possess a function in biosynthesis upstream of lepA (PubMed:26051490). Leporin B is further oxidized in the presence of ferric ion to give the leporin B trimer-iron chelate, but whether or not this reaction is catalyzed by an enzyme in the pathway or by ferric ion is not determined yet (PubMed:26051490).<ref>PMID:26051490</ref> <ref>PMID:20447271</ref> |
| <div style="background-color:#fffaf0;">
| |
| == Publication Abstract from PubMed ==
| |
| LepI is a novel multifunctional enzyme that catalyzes stereoselective dehydration, Diels-Alder reaction, and retro-Claisen rearrangement. Here we report the crystal structure of LepI in complex with its co-factor S-adenosyl methionine (SAM). LepI forms a tetramer via the N-terminal helical domain and binds to a SAM molecule in the C-terminal catalytic domain. The binding modes of various LepI substrates are investigated by docking simulations, which suggest that the substrates are bound via both hydrophobic and hydrophilic forces, as well as cation-pi interactions with the positively charged SAM. The reaction starts with a dehydration step in which H133 possibly deprotonates the pyridone hydroxyl group of the substrate, while D296 might protonate an alkyl-chain hydroxyl group. Subsequent pericyclization may be facilitated by the correct fold of the substrate's alkyl chain and a thermodynamic driving force towards sigma-bonds at the expense of pi-bonds. These results provide structural insights into LepI catalysis and are important in understanding the mechanism of enzymatic pericyclization.
| |
| | |
| Crystal structure of LepI, a multifunctional SAM-dependent enzyme which catalyzes pericyclic reactions in leporin biosynthesis.,Chang Z, Ansbacher T, Zhang L, Yang Y, Ko TP, Zhang G, Liu W, Huang JW, Dai L, Guo RT, Major DT, Chen CC Org Biomol Chem. 2019 Feb 20;17(8):2070-2076. doi: 10.1039/c8ob02758g. PMID:30628619<ref>PMID:30628619</ref>
| |
| | |
| From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| |
| </div>
| |
| <div class="pdbe-citations 5zzd" style="background-color:#fffaf0;"></div>
| |
| == References == | | == References == |
| <references/> | | <references/> |
| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
| [[Category: Aspfn]] | | [[Category: Aspergillus flavus NRRL3357]] |
| [[Category: Large Structures]] | | [[Category: Large Structures]] |
| [[Category: Chang, Z Y]] | | [[Category: Chang ZY]] |
| [[Category: Chen, C C]] | | [[Category: Chen CC]] |
| [[Category: Guo, R T]] | | [[Category: Guo RT]] |
| [[Category: Liu, W D]] | | [[Category: Liu WD]] |
| [[Category: Sam]]
| |
| [[Category: Substrate binding]]
| |
| [[Category: Transferase]]
| |