6P7C

D104A/S128A S. typhimurium siroheme synthase

6P7C の概要

• エントリーDOI: 10.2210/pdb6p7c/pdb
• 関連するPDBエントリー: 1PJS
• 分子名称: Siroheme synthase, S-ADENOSYL-L-HOMOCYSTEINE, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: siroheme, sirohydrochlorin, precorrin-2, tetrapyrrole biosynthesis, cysg, transferase
• 由来する生物種: Salmonella typhimurium
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 101097.25

構造登録者

Pennington, J.M.,Stroupe, M.E. (登録日: 2019-06-05, 公開日: 2020-02-26, 最終更新日: 2023-10-11)

主引用文献

Pennington, J.M.,Kemp, M.,McGarry, L.,Chen, Y.,Stroupe, M.E.
Siroheme synthase orients substrates for dehydrogenase and chelatase activities in a common active site.
Nat Commun, 11:864-864, 2020

PubMed Abstract: 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.

PubMed: 32054833
DOI: 10.1038/s41467-020-14722-1

実験手法

X-RAY DIFFRACTION (2.76 Å)