ヘムタンパク質とモデルシステムのFe-N-O結合に関する密度関数理論の調査
Yong Zhang1, William Gossman, Eric Oldfield
1Department of Chemistry, 600 South Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Journal of the American Chemical Society
|December 25, 2003
まとめ
密度関数理論は,ニトロシルヘム複合体のモースバウアー光譜とEPR超精密結合定数を正確に計算します. これにより,金属タンパク質における鉄-ニトロシル結合の幾何学を正確に決定することができます.
科学分野:
- コンピューティング・ケミストリー
- バイオフィジックス 生物物理学
- 量子力学は,量子力学という
背景:
- ニトロシルヘム複合体は,生物学的システムにおいて極めて重要です.
- 鉄-ニトロシル幾何学の正確な決定は,タンパク質の機能を理解するために不可欠です.
- 以前の計算方法では,これらの幾何学を予測する上で限界がありました.
研究 の 目的:
- 密度関数理論 (DFT) の計算をNOヘムモデル化合物のモースバウアー四極分裂と同位体シフトのために行う.
- Fe (II) (NO) (イミダゾール) 複合体のモデルについて,Mössbauerパラメータと電子パラマグネティック共鳴 (EPR) の超精密結合定数を計算する.
- ニトロシルヘモグロビンのFe-NO結合長とFe-N-O結合角度をZ表面アプローチを用いて決定する.
主な方法:
- 密度関数理論 (DFT) の計算.密度関数理論 (DFT) の計算.密度関数理論 (DFT) の計算.密度関数理論 (DFT) の計算.密度関数理論 (DFT) の計算.密度関数理論 (DFT) の計算.
- モースバウアー四極分裂と同位体シフトの計算.
- 電子パラマグネティック共振 (EPR) 超精密結合定数計算.
- 債券幾何学的確率を決定するためのプロパティ表面とZ表面の計算.
主要な成果:
- DFTの計算は,NOヘムモデルにおける理論的および実験的なMössbauerデータとの間の良好な一致を示した.
- Z表面アプローチにより,最も可能性が高いFe-NO結合長が1.79 Åで,Fe-N-O結合角度が136°137°で,ニトロシルヘモグロビンの場合が得られました.
- 水素結合複合体の計算された幾何学は,タンパク質に存在する幾何学と一致していた.
- 高度なFe-N-O角または非常に長いFe-NO結合長がタンパク質にエネルギー的に不利であることが判明しました.
結論:
- モッズバウアー光譜法とEPR超精密結合定数は,ニトロシルヘム系において正確に計算できます.
- 計算によるアプローチにより,金属タンパク質のFe-N-O幾何学を正確に決定することができます.
- Z表面法は,二磁性 (CO) および二磁性 (NO) ヘムタンパク質の両方に適用できます.
- タンパク質における金属-リガンド結合の幾何学は,モデルシステムで観察された幾何学に非常に似ています.
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