電子捕獲解離は,ペプチドアミド水素の分子内移動の低度で進行する
Kasper D Rand1, Christopher M Adams, Roman A Zubarev
1Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Journal of the American Chemical Society
|January 4, 2008
まとめ
電子捕捉解離 (ECD) は,ガス相タンパク質解析における水素の乱れを最小限に抑えます. この方法はデュテリウム濃度を正確に決定し,水素デュテリウム交換質量スペクトロメトリ (HX-MS) 研究における単一残留物の解消を可能にします.
科学分野:
- バイオケミストリー バイオケミストリー
- アナリティカル・ケミストリー (Analytical Chemistry) とは
- 構造生物学 構造生物学とは
背景:
- 水素デウテリウム交換質量スペクトロメトリ (HX-MS) は,タンパク質の動態を分析する.
- デウテリウムの局所化のための現在の方法は,残留分辨率に制限があります.
- ガス相断片化は,HX-MSの適用性を高めるための鍵です.
研究 の 目的:
- 電子捕獲解離 (ECD) 過程における分子内水素移動を評価する.
- ペプチドにおけるサイト固有のデウテリウム濃度の測定のためのECDの可能性を評価する.
- デュテリウムラベリングの保存のために,ECDと衝突誘発解離 (CID) を比較する.
主な方法:
- 選択的にデュテリウムラベル付ペプチドを使用して,分子内水素 (1H/2H) 移行を調査した.
- 電子捕獲解離 (ECD) と衝突誘発解離 (CID) をガス相断片化に使用した.
- デウテリウムの組み込みパターンのための分析されたc-およびz-断片イオン.
主要な成果:
- ECD中の振動刺激の最小化は,限られた水素乱雑をもたらしました.
- 過剰な振動刺激またはCIDは,広範囲の水素乱雑を引き起こしました.
- ECDによって生成された断片イオンは,溶液相デュテリウムラベルパターンを正確に反映した.
結論:
- ECDは,HX-MSにおけるサイト固有のデュテリウム分析の有望な方法である.
- ECDは,水素の移動を減少させることで,従来の断片化方法の限界を克服します.
- この技術は,タンパク質の構造動態分析のための単一残留物の分解を容易にする.
関連する概念動画
01:20Mass Spectrometry: Molecular Fragmentation Overview
The ionization of a molecule into a molecular ion inside the mass spectrometer causes instability in the molecule's structure due to the loss of an electron. This eventually leads to the fragmentation or breaking of some bonds in the molecule. The fragmentation occurs predominantly at specific bonds to yield relatively stable fragments.
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
01:01Mass Spectrometry: Carboxylic Acid, Ester, and Amide Fragmentation
The fragmentation patterns observed for compounds such as carboxylic acids, esters, and amides in the mass spectra include ⍺-cleavage and McLafferty rearrangement. Fragmentation by ⍺-cleavage preferentially occurs at the carbon-carbon bond at the ⍺-position next to the carboxylic group to generate a neutral radical and a cation. Long chain compounds with hydrogen at their γ-carbon undergo McLafferty rearrangement to give a radical cation and a neutral alkene.
For example, the fragmentation of...
For example, the fragmentation of...
01:15Mass Spectrometry of Amines
In mass spectroscopy, amines undergo fragmentation to give parent ions with odd molecule weights. This observed mass spectrum follows the nitrogen rule; a molecule with an odd number of nitrogen atoms produces a molecular ion with an odd molecular weight. Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit strong molecular ion peaks, but acyclic aliphatic amines show...
00:55Mass Spectrometry: Amine Fragmentation
Amines can be identified using mass spectroscopy based on their characteristic fragmentation patterns. The molecular ions of amines undergo fragmentation via ⍺-cleavage. The ⍺-cleavage of the carbon-carbon bonds in amines generates an alkyl radical and resonance-stabilized nitrogen-containing cation.
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
01:28Amides to Carboxylic Acids: Hydrolysis
Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
01:21Chemical Ionization (CI) Mass Spectrometry
The molecular ion peak of a molecule in the mass spectrum provides vital information for molecular identification. However, conventional electron impact ionization can lead to the rapid dissociation of some molecular ions before they reach the detector. A milder ionization method is required to increase the lifetime of such ionized analyte molecules. Chemical ionization (CI) is a gas-phase protonation reaction useful for mass-analyzing analyte molecules that are easily protonated to yield the...