1H6N

Formation of a tyrosyl radical intermediate in Proteus mirabilis catalase by directed mutagenesis and consequences for nucleotide reactivity

1H6N の概要

• エントリーDOI: 10.2210/pdb1h6n/pdb
• 関連するPDBエントリー: 1E93 2CAE 2CAF 2CAG 2CAH
• 分子名称: CATALASE, PROTOPORPHYRIN IX CONTAINING FE, ACETATE ION, ... (5 entities in total)
• 機能のキーワード: oxidoreductase (h2o2 acceptor), peroxidase, iron, hem, hydrogen peroxide, nadp
• 由来する生物種: PROTEUS MIRABILIS
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 56513.94

構造登録者

Andreoletti, P.,Sainz, G.,Jaquinod, M.,Gagnon, J.,Jouve, H.M. (登録日: 2001-06-20, 公開日: 2003-10-03, 最終更新日: 2024-10-16)

主引用文献

Andreoletti, P.,Sainz, G.,Jaquinod, M.,Gagnon, J.,Jouve, H.M.
High Resolution Structure and Biochemical Properties of a Recombinant Proteus Mirabilis Catalase Depleted in Iron.
Proteins: Struct.,Funct., Genet., 50:261-, 2003

PubMed Abstract: Heme catalases are homotetrameric enzymes with a highly conserved complex quaternary structure, and their functional role is still not well understood. Proteus mirabilis catalase (PMC), a heme enzyme belonging to the family of NADPH-binding catalases, was efficiently overexpressed in E. coli. The recombinant catalase (rec PMC) was deficient in heme with one-third heme and two-thirds protoporphyrin IX as determined by mass spectrometry and chemical methods. This ratio was influenced by the expression conditions, but the enzyme-specific activity calculated relative to the heme content remained unchanged. The crystal structure of rec PMC was solved to a resolution of 2.0 A, the highest resolution obtained to date with PMC. The overall structure was quite similar to that of wild-type PMC, and it is surprising that the absence of iron had no effect on the structure of the active site. Met 53 close to the essential His 54 was found less oxidized in rec PMC than in the wild-type enzyme. An acetate anion was modeled in an anionic pocket, away from the heme group but important for the enzymatic reaction. An alternate conformation observed for Arg 99 could play a role in the formation of the H-bond network connecting two symmetrical subunits of the tetramer.

PubMed: 12486720
DOI: 10.1002/PROT.10283

実験手法

X-RAY DIFFRACTION (2.11 Å)