リボヌクレオチドリドゥクタゼのサブユニットインターフェースのプロトン転送ネットワークによって促進されるラジカル輸送
Chang Cui1, David Y Song1, Catherine L Drennan2,3,4
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
Journal of the American Chemical Society
|February 22, 2023
まとめ
リボヌクレオチド還元酵素 (RNR) はDNA合成に不可欠である. この研究は,RNR酵素活性とデオキシヌクレオチド形成に不可欠な特定の残留物を含むプロトンシャトルネットワークを明らかにしています.
科学分野:
- 生物化学
- 酵素学
- 分子生物学
背景:
- リボヌクレオチド還元酵素 (RNRs) は,デオキシヌクレオチド合成を触媒する重要な酵素である.
- エシェリキア・コロイのクラスIアRNRは,αとβサブユニットを含み,αα'ββ'複合体を形成する.
- 遠距離プロトン結合電子伝送経路はRNR活動に不可欠です.
研究 の 目的:
- RNR機能におけるY356[β]残留と関連する極性ネットワークの役割を明らかにする.
- *E. coli*クラスIa RNRのα/βインターフェイスにおける陽子転送機構を調査する.
主な方法:
- カノニカルおよび非自然なアミノ酸を用いたサイト指向型変異.
- Y356 基の光化学的生成
- 暫定吸収スペクトル検査とデオキシヌクレオチド形成検査
主要な成果:
- Y356[β]残基とY731[α]はα/βインターフェイスを横切っている.
- 残留物のネットワーク (E52[β],R331[α],E326[α],E326[α']) は,Y356の酸化に不可欠である.
- このネットワークは,Y356酸化時にインターフェイスから大量溶媒へのプロトンシャトルを容易にします.
結論:
- 特定された極性ネットワーク (E52[β],R331[α],E326[α],E326[α']) はRNR活動に不可欠である.
- このネットワークは,RNRの触媒サイクルをサポートし,陽子転送において重要な役割を果たします.
- このメカニズムを理解することで,デオキシヌクレオチド生物合成の調節に関する洞察が得られます.
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