タンパク質の進化におけるアミノ酸の増減の普遍的な傾向である
I King Jordan1, Fyodor A Kondrashov, Ivan A Adzhubei
1National Center for Biotechnology Information, NIH, Bethesda, Maryland 20894, USA.
Nature
|January 22, 2005
まとめ
タンパク質の進化は,生涯を通じて一貫したアミノ酸の変化を示しています. システイン,メチオニン,ヒスティジン,セリン,フェニララニンが増加し,プロリン,アラニン,グルタミン酸,グリシンが減少しています.
科学分野:
- 進化生物学の進化生物学について
- 分子進化は分子進化である.
- ゲノミクスゲノミクスとは
背景:
- タンパク質のアミノ酸の組成は,種によって大きく変化し,時間とともに進化します.
- 生物のゲノム組成 (例えば,高グアニン-サイトシンまたはアデニン-チミン含有量) は,タンパク質のアミノ酸周波数に影響します.
- 進行中のアミノ酸の周波数変化の普遍的なパターンは,以前は特定されていませんでした.
研究 の 目的:
- 多種多様な分類で進行中のアミノ酸置換の普遍的な傾向を調査する.
- 現在,ヒトのタンパク質でアミノ酸の周波数変化が起きているかどうかを判断する.
- 観察されたアミノ酸の頻度傾向と,アミノ酸の遺伝コードへの歴史的採用を相関させる.
主な方法:
- 15種多様な種 (バクテリア,アーカイア,ユーカリオタ) のオートロゴスタンパク質の比較分析.
- アミノ酸の置換を二極化し,進化の方向性を推論するために,系統遺伝学的方法を利用した.
- 現在のアミノ酸の傾向を評価するために,ヒトゲノムにおける非同義単核酸多形態を分析した.
主要な成果:
- アミノ酸の蓄積と損失の一貫したパターンは,研究された15種のうち14種で観察されました.
- システイン,メチオニン,ヒスティジン,セリン,フェニララニンの頻度は増加した.
- プロリン,アラニン,グルタミン酸,およびグリシンの頻度は一貫して減少しました.
- 人間のタンパク質の進化は,同じ9つのアミノ酸が増加または減少を示し,これらの広範な傾向を反映しています.
- アミノ酸の頻度の増加は,遺伝コードへの遅い採用と相関し,頻度の減少は,早期の組み込みと相関する.
結論:
- アミノ酸の周波数の膨張と収縮という普遍的な進化的傾向が,生命のあらゆる領域で進行しています.
- 当初は過小評価されていたアミノ酸の拡大は,34億年以上前に始まり,今日も続いている.
- 観察されたパターンは,遺伝子コードとタンパク質の進化のダイナミックな性質についての洞察を提供します.
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