モノチオールグルタレドキシンには,IscUの支架タンパク質に組み立てられた[Fe2S2]クラスタを貯蔵および輸送する機能があります
Priyanka Shakamuri1, Bo Zhang, Michael K Johnson
1Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia 30602, USA.
Journal of the American Chemical Society
|September 12, 2012
まとめ
分子チャペロンであるHscAとHscBは,バクテリアの鉄硫黄クラスター組成に不可欠な IscU から Grx5 への鉄硫黄クラスター移転を著しく加速します. これは,効率的なin vitro研究のためにこれらのコチャペロンが必要であることを強調しています.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 微生物学 微生物学とは
背景:
- 鉄硫黄 (Fe-S) クラスターは,多くのタンパク質の重要な共因子である.
- バクテリアの鉄硫黄クラスター (ISC) アセンブリ機械は,IscUのような脚架タンパク質と分子コチャペロンであるHscAとHscBを含む.
- IscUはFe-Sクラスターの組み立てのための主要な支架として機能し,HscAとHscBはATP依存のクラスター転送を促進します.
研究 の 目的:
- 分子コチャペロンであるHscAおよびHscBが,IscUからApo-Grx5.5へのFe-Sクラスターの移転における役割を調査する.
- HscA/HscB/Mg-ATPによって媒介されるFe-Sクラスター転送の速度向上を定量化する.
主な方法:
- [Fe(2) S(2) ](2+) クラスターの移転を監視するために,円形の二重化 (CD) スペクトロスコーピーを利用しました.
- [Fe(2) S(2) ](2+) 結合 IscU から apo-Grx5 に HscA/HscB/Mg-ATP が存在しない場合と存在する場合のクラスター転送率を比較した.
- 移転プロセスの第2次レート定数を決定しました.
主要な成果:
- HscA/HscB/Mg-ATPの存在下での[Fe(2) S(2) ](2+) クラスタの移転率の700倍の増加が観察されました.
- HscA/HscB媒介による伝送のために,23°Cで20,000 M−1 min−1の第2次速度定数を計算した.
- HscAとHscBは,IscUからGrx5.5への効率的なATP依存 [Fe(2) S(2) ](2+) クラスター転送に不可欠であることを実証しました.
結論:
- HscAとHscBは,IscUからGrx5.5への効率的なATP依存 [Fe(2) S(2) ](2+) クラスター転送に不可欠です.
- モノチオールグルタレドキシン (Grx's) は,IscUに組み立てられたFe-Sクラスタの貯蔵と輸送に役割を果たしている可能性が高い.
- [Fe(2) S(2) ](2+) -IscUのクラスター移転に関する試験では,正確な解釈のためにHscA/HscBコチャペロンシステムを含めることが必要です.
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