設計されたベータヘアピンにおける横鎖と横鎖の相互作用:横断と横断の両方のペアリングの重要性

F A Syud¹, H E Stanger, S H Gellman

¹Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.

Journal of the American Chemical Society

|September 6, 2001

まとめ

糸間側鎖の接触は,ベータシート構造を著しく安定させる. ベータシート回転に起因する"横"の水性相互作用と"対角"の接触の両方が,ベータヘアピン安定性を高めます.

科学分野:

バイオケミストリーバイオケミストリー
構造生物学構造生物学とは
タンパク質の折りたたみ

背景:

ベータシートは,重要なタンパク質の二次構造である.
アミノ酸のサイドチェーン間の相互作用は,タンパク質の安定性に影響を与えます.
これらの相互作用を研究するために,自律的に折りたたむβヘアピンモデルが使用されています.

研究の目的:

ベータ-ヘアピン安定性におけるインターストランドサイドチェーン・サイドチェーンコンタクトの役割を調査する.
ベータシート構造に対する特定の横および対角接触の貢献を決定する.
変異する重要な残留物の構成的影響を評価する.

主な方法:

自律的に折りたたむベータヘアピンモデルシステム (RYVEV(D) PGOKILQ-NH2) を利用しました.
特定の残留物 (Tyr-2,Lys-9,Leu-11) をアラニンまたはセリンで置き換え,サイト指向型変異を生成した.
生物物理的技術 (NOE分析によって示唆される) を用いて構成変化の評価.

主要な成果:

Tyr-2とLeu-11 (横の非水素結合ペア) を変異させることで,アラニン/セリンはベータヘアピン安定性に影響を及ぼした.
変異したTyr-2とLys-9 (対角線交配) も,形状の安定性に影響した.
防水性の横接点と対角接点は,ベータヘアピン安定性に寄与する.

結論:

横と対角の両方,横鎖と横鎖の接触は,ベータ-ヘアピン安定性にとって重要です.
発見は,βシート構造の既存のモデルと,タンパク質結晶構造の統計分析と一致しています.
この研究は,ベータシートにおける対角線間相互作用の安定作用の証拠を提供します.

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