6p5z

<table><tr><td colspan='2'>[[6p5z]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_typhimurium"_loeffler_1892 "bacillus typhimurium" loeffler 1892]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6P5Z OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6P5Z FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=F0X:cobalt-sirohydrochlorin'>F0X</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[6p5x|6p5x]]</div></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">cobA, cysG, C2253_19735, CET98_25025, D7F20_23535, D7H43_21790, DJ388_17225, NCTC13348_03825 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=90371 "Bacillus typhimurium" Loeffler 1892])</td></tr>

== Function ==

[[https://www.uniprot.org/uniprot/A0A0F7JCI1_SALER A0A0F7JCI1_SALER]] Multifunctional enzyme that catalyzes the SAM-dependent methylations of uroporphyrinogen III at position C-2 and C-7 to form precorrin-2 via precorrin-1. Then it catalyzes the NAD-dependent ring dehydrogenation of precorrin-2 to yield sirohydrochlorin. Finally, it catalyzes the ferrochelation of sirohydrochlorin to yield siroheme.[HAMAP-Rule:MF_01646][SAAS:SAAS00971394]

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== Publication Abstract from PubMed ==

Siroheme is the central cofactor in a conserved class of sulfite and nitrite reductases that catalyze the six-electron reduction of sulfite to sulfide and nitrite to ammonia. In Salmonella enterica serovar Typhimurium, siroheme is produced by a trifunctional enzyme, siroheme synthase (CysG). A bifunctional active site that is distinct from its methyltransferase activity catalyzes the final two steps, NAD(+)-dependent dehydrogenation and iron chelation. How this active site performs such different chemistries is unknown. Here, we report the structures of CysG bound to precorrin-2, the initial substrate; sirohydrochlorin, the dehydrogenation product/chelation substrate; and a cobalt-sirohydrochlorin product. We identified binding poses for all three tetrapyrroles and tested the roles of specific amino acids in both activities to give insights into how a bifunctional active site catalyzes two different chemistries and acts as an iron-specific chelatase in the final step of siroheme synthesis.

Siroheme synthase orients substrates for dehydrogenase and chelatase activities in a common active site.,Pennington JM, Kemp M, McGarry L, Chen Y, Stroupe ME Nat Commun. 2020 Feb 13;11(1):864. doi: 10.1038/s41467-020-14722-1. PMID:32054833<ref>PMID:32054833</ref>

 

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

[[Category: Bacillus typhimurium loeffler 1892]]

[[Category: Pennington, J M]]

[[Category: Stroupe, M E]]

[[Category: Tetrapyrrole biosynthesis]]