![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
第2球は,鉄 (III) 超酸化物ディスミュータゼにおける基質-アナログ結合に寄与する
Juan Xie1, Emine Yikilmaz, Anne-Frances Miller
1Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Journal of the American Chemical Society
|April 4, 2002
まとめ
研究者らは,スペクトロスコピーと計算を用いて,鉄 (III) スーパーオキシードジスミュータゼ (FeSOD) アジドクトを研究した. 彼らは単一のアジドリガンドを発見し,Fe-N-N結合角度の差異がこれらの重要な酵素複合体の異なる色を説明することを提案しました.
科学分野:
- バイオケミストリー バイオケミストリー
- バイオ・オーガニック化学 バイオ・オーガニック化学
- コンピューティング・ケミストリー
背景:
- 鉄 (III) 超酸化物変異酵素 (FeSOD) は,活性酸素種に対する細胞防御に不可欠です.
- FeSODの低温アジドクトは,黄色とピンクの特徴的な形を示し,その構造的基礎は20年以上にわたって不明のままである.
研究 の 目的:
- 鉄(III) 超酸化物ディスミュータゼ (N(3) -FeSODの黄色とピンクのアジドクトの構造と電子特性を解明する.
- アジドリガンドの数に関する不一致を解決し,スペクトル変化に寄与する要因を理解する.
主な方法:
- 変数温度,変数フィールドの磁気円二極化 (MCD) スペクトロスコーピー.
- 共振ラーマン (RR) 光譜法.共振ラーマン (RR) 光譜法.
- 密度関数理論 (DFT) と半経験的INDO/S-CI計算モデリング.
主要な成果:
- 顕微鏡データによると,黄色とピンクの両方のN(3) -FeSOD種において,単一のアジドリガンドがフェリック中心に結合しており,以前の仮説に異議を唱えている.
- 共振ラーマンスペクトルはFe-N(3) 結合の微妙な違いを明らかにし,ワイルドタイプとQ69E変異体の形態に一貫しています.
- 計算的研究は単一のアジドモデルを支持し,スペクトル変異をFe-N-N結合角度の差異に属し, ~10°の変異が色差を説明します.
結論:
- N(3) -FeSODアダクトの独特の色は,第2の協調球の影響を受けたFe-N-N結合角度の変動から生じる.
- 2番目の調整球は,活性部位の幾何学を調節し,酵素活性のための潜在的に基板の方向性を調整する役割を果たします.
さらに関連する動画
関連する概念動画
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
02:51Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
00:56Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...