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==Crystal structure of a low activity F12L mutant of human porphobilinogen synthase== | |||
<StructureSection load='1pv8' size='340' side='right'caption='[[1pv8]], [[Resolution|resolution]] 2.20Å' scene=''> | |||
| | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1pv8]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PV8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PV8 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]] 2.2Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PB1:3-(2-AMINOETHYL)-4-(AMINOMETHYL)HEPTANEDIOIC+ACID'>PB1</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=1pv8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1pv8 OCA], [https://pdbe.org/1pv8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1pv8 RCSB], [https://www.ebi.ac.uk/pdbsum/1pv8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1pv8 ProSAT]</span></td></tr> | |||
</table> | |||
== Disease == | |||
[https://www.uniprot.org/uniprot/HEM2_HUMAN HEM2_HUMAN] Defects in ALAD are the cause of acute hepatic porphyria (AHEPP) [MIM:[https://omim.org/entry/612740 612740]. A form of porphyria. Porphyrias are inherited defects in the biosynthesis of heme, resulting in the accumulation and increased excretion of porphyrins or porphyrin precursors. They are classified as erythropoietic or hepatic, depending on whether the enzyme deficiency occurs in red blood cells or in the liver. AHP is characterized by attacks of gastrointestinal disturbances, abdominal colic, paralysis, and peripheral neuropathy. Most attacks are precipitated by drugs, alcohol, caloric deprivation, infections, or endocrine factors.<ref>PMID:1569184</ref> <ref>PMID:2063868</ref> <ref>PMID:1309003</ref> <ref>PMID:10706561</ref> <ref>PMID:17236137</ref> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/HEM2_HUMAN HEM2_HUMAN] Catalyzes an early step in the biosynthesis of tetrapyrroles. Binds two molecules of 5-aminolevulinate per subunit, each at a distinct site, and catalyzes their condensation to form porphobilinogen.<ref>PMID:11032836</ref> <ref>PMID:19812033</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/pv/1pv8_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=1pv8 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Porphobilinogen synthase (PBGS) catalyzes the first common step in the biosynthesis of tetrapyrroles (such as heme and chlorophyll). Although the predominant oligomeric form of this enzyme, as inferred from many crystal structures, is that of a homo-octamer, a rare human PBGS allele, F12L, reveals the presence of a hexameric form. Rearrangement of an N-terminal arm is responsible for this oligomeric switch, which results in profound changes in kinetic behavior. The structural transition between octamer and hexamer must proceed through an unparalleled equilibrium containing two different dimer structures. The allosteric magnesium, present in most PBGS, has a binding site in the octamer but not in the hexamer. The unprecedented structural rearrangement reported here relates to the allosteric regulation of PBGS and suggests that alternative PBGS oligomers may function in a magnesium-dependent regulation of tetrapyrrole biosynthesis in plants and some bacteria. | Porphobilinogen synthase (PBGS) catalyzes the first common step in the biosynthesis of tetrapyrroles (such as heme and chlorophyll). Although the predominant oligomeric form of this enzyme, as inferred from many crystal structures, is that of a homo-octamer, a rare human PBGS allele, F12L, reveals the presence of a hexameric form. Rearrangement of an N-terminal arm is responsible for this oligomeric switch, which results in profound changes in kinetic behavior. The structural transition between octamer and hexamer must proceed through an unparalleled equilibrium containing two different dimer structures. The allosteric magnesium, present in most PBGS, has a binding site in the octamer but not in the hexamer. The unprecedented structural rearrangement reported here relates to the allosteric regulation of PBGS and suggests that alternative PBGS oligomers may function in a magnesium-dependent regulation of tetrapyrrole biosynthesis in plants and some bacteria. | ||
Control of tetrapyrrole biosynthesis by alternate quaternary forms of porphobilinogen synthase.,Breinig S, Kervinen J, Stith L, Wasson AS, Fairman R, Wlodawer A, Zdanov A, Jaffe EK Nat Struct Biol. 2003 Sep;10(9):757-63. Epub 2003 Aug 3. PMID:12897770<ref>PMID:12897770</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1pv8" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Porphobilinogen synthase|Porphobilinogen synthase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Breinig S]] | |||
[[Category: Breinig | [[Category: Fairman R]] | ||
[[Category: Fairman | [[Category: Jaffe EK]] | ||
[[Category: Jaffe | [[Category: Kervinen J]] | ||
[[Category: Kervinen | [[Category: Stith L]] | ||
[[Category: Stith | [[Category: Wasson AS]] | ||
[[Category: Wasson | [[Category: Wlodawer A]] | ||
[[Category: Wlodawer | [[Category: Zdanov A]] | ||
[[Category: Zdanov | |||