古代のタンパク質の結晶構造:構造的エピスタシスによる進化
Eric A Ortlund1, Jamie T Bridgham, Matthew R Redinbo
1Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA.
まとめ
研究者らは,脊椎動物のグルココルチコイド (GR) およびミネラルコルチコイド (MR) 受容体への古代のタンパク質前駆体を復活させました. 構造分析により,GRを牽引する重要な変異が明らかになった.
科学分野:
- 進化生物学の進化生物学について
- 構造生物学 構造生物学とは
- 分子進化は分子進化である.
背景:
- タンパク質の進化を理解することは,機能的多様化の解読に不可欠です.
- グルココルチコイド (GR) やミネラルコルチコイド (MR) のようなホルモン受容体の進化経路は,ほとんど不明のままである.
- 祖先のタンパク質構造の直接的な証拠は稀であり,機能的移行に関する洞察を制限しています.
研究 の 目的:
- 新しいタンパク質機能の進化の基礎となる構造的メカニズムを解明する.
- 脊椎動物のGRおよびMR受容体の祖先の前駆体を再構築し,分析する.
- MRのような祖先からGRの分岐に起因する特定の歴史的変異を特定する.
主な方法:
- 4億5千万年前の祖先のタンパク質の復活.
- 祖先のタンパク質の構造を決定するX線結晶学.
- 進化的変化を追跡するための統合された構造的,系統的,機能的分析.
主要な成果:
- 復活した祖先のGR/MR前駆体の結晶構造が得られた.
- GRホルモン特異性の進化を再現する特定の歴史的変異が特定されました.
- これらの変異は,エピスタシスと許容性変異によって誘発される受容体-リガンドとイントラタンパク質の相互作用を変化させた.
結論:
- MRのような祖先からのGRホルモン特異性の進化には,特定の残留物の再配置が含まれていました.
- エピスタティック相互作用と"許容性"変異は,機能的シフトを可能にするために重要である.
- この研究は,ホルモン受容体の進化軌道の直接的な構造的証拠を提供します.
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