アロマティックアミノ酸の混乱は,リボヌクレオチド還元酵素の鉄のクラスター組成と関連しています
Adam R Offenbacher1, Jun Chen, Bridgette A Barry
1Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Journal of the American Chemical Society
|April 14, 2011
まとめ
この研究では,紫外線共振ラーマン光譜を用いて,リボヌクレオチド還元酵素 (RNR) の構造変化を明らかにしました. 鉄のクラスター組立とチロシルラジカル減少がアロマティックアミノ酸にどのように影響するかを詳細に説明し,酵素調節に関する洞察を提供します.
科学分野:
- バイオケミストリー バイオケミストリー
- スペクトル顕微鏡検査です.
- 酵素学 酵素学とは
背景:
- クラスIaのリボヌクレオチド還元酵素 (RNR) は,ダイアイロンクラスターとチロシル基を含む必須酵素である.
- RNRの構造的動態を理解することは,酵素の機能と調節を解明するために不可欠です.
- アロマティックアミノ酸は,酵素の構造と活性において重要な役割を果たします.
研究 の 目的:
- 鉄のクラスター組立によって誘発されたRNR β2サブユニットの構造変化を調査する.
- タイロシル基 (Y122•) の減少に関連した構造的変化を特徴づける.
- RNRの構造と機能における芳香性アミノ酸 (チロシン,トリプトファン,ヒスティジン) の役割を探求する.
主な方法:
- 紫外線共振ラーマン (UVRR) 差分光譜を用いた.
- UVRRスペクトルは229nmで強化され,芳香性アミノ酸の貢献度が探査されました.
- 同位体ラベリングとモデル化合物の比較がスペクトル割り当てに使用されました.
主要な成果:
- ティロシル基の還元により,Y122•およびY122の特定のラマン帯が得られ,他の芳香質残留物の干渉は最小限に抑えられた.
- 鉄のクラスター・アセンブリが誘導したヒスティジンのデプロトネーションは,p(2) Hの定位試験によって支持され,pKの上昇を示した.
- タイロシンとトリプトファンの混乱が観察されました;トリプトファンの変化は,水素結合の増加と金属中心付近の形状の変化を示唆します.
結論:
- アロマティックアミノ酸の静電および構成の変化は,RNRにおける金属クラスター組立に伴います.
- 混乱したトリプトファンの残留物は,金属の中心に近い保護された低ダイエレクトリック環境にあります.
- これらの形状の変化は,RNRにおける金属結合のアロステリック調節に寄与する可能性がある.
関連する概念動画
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Translation Produces the Building Blocks of Life
01:31Translation
Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
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02:53Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
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