6p5z

<table><tr><td colspan='2'>[[6p5z]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Salmonella_enterica_subsp._enterica_serovar_Typhimurium Salmonella enterica subsp. enterica serovar Typhimurium]. 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>

== Function ==

[https://www.uniprot.org/uniprot/CYSG_SALTY CYSG_SALTY] 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.<ref>PMID:14595395</ref>

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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>

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== References ==

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[[Category: Salmonella enterica subsp. enterica serovar Typhimurium]]