1FGO

LIPOXYGENASE-1 (SOYBEAN) AT 100K, Q495A MUTANT

1FGO の概要

• エントリーDOI: 10.2210/pdb1fgo/pdb
• 関連するPDBエントリー: 1F8N 1FGM 1FGQ 1FGR 1FGT 1YGE
• 分子名称: SEED LIPOXYGENASE-1, FE (III) ION (3 entities in total)
• 機能のキーワード: dioxygenase, lipoxygenase, metalloprotein, fatty acids, oxidoreductase
• 由来する生物種: Glycine max (soybean)
• 細胞内の位置: Cytoplasm: P08170
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 94478.92

構造登録者

Tomchick, D.R.,Minor, W.,Holman, T. (登録日: 2000-07-28, 公開日: 2001-07-04, 最終更新日: 2023-08-09)

主引用文献

Tomchick, D.R.,Phan, P.,Cymborowski, M.,Minor, W.,Holman, T.R.
Structural and functional characterization of second-coordination sphere mutants of soybean lipoxygenase-1.
Biochemistry, 40:7509-7517, 2001

PubMed Abstract: Lipoxygenases are an important class of non-heme iron enzymes that catalyze the hydroperoxidation of unsaturated fatty acids. The details of the enzymatic mechanism of lipoxygenases are still not well understood. This study utilizes a combination of kinetic and structural probes to relate the lipoxygenase mechanism of action with structural modifications of the iron's second coordination sphere. The second coordination sphere consists of Gln(495) and Gln(697), which form a hydrogen bond network between the substrate cavity and the first coordination sphere (Asn(694)). In this investigation, we compared the kinetic and structural properties of four mutants (Q495E, Q495A, Q697N, and Q697E) with those of wild-type soybean lipoxygenase-1 and determined that changes in the second coordination sphere affected the enzymatic activity by hydrogen bond rearrangement and substrate positioning through interaction with Gln(495). The nature of the C-H bond cleavage event remained unchanged, which demonstrates that the mutations have not affected the mechanism of hydrogen atom tunneling. The unusual and dramatic inverse solvent isotope effect (SIE) observed for the Q697E mutant indicated that an Fe(III)-OH(-) is the active site base. A new transition state model for hydrogen atom abstraction is proposed.

PubMed: 11412104
DOI: 10.1021/bi002893d

実験手法

X-RAY DIFFRACTION (1.62 Å)