ポリペプチドカチオンの電子移転解離に起因するカチオン充電部位の同一性と位置の影響

Yu Xia¹, Harsha P Gunawardena, David E Erickson

¹Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.

Journal of the American Chemical Society

|September 21, 2007

まとめ

カチオン充電部位はペプチドのガス相イオン/イオン反応に大きく影響する. 陽子化されたヒスティジンは解離なしの電子移転を好み,アルギニンとライシンは異なるサイドチェーンの断片化パターンを示しています.

科学分野:

アナリティカル・ケミストリー (Analytical Chemistry) とは
物理化学物理化学
バイオケミストリーバイオケミストリー

背景:

ガス相イオン/イオン反応はペプチド分析において極めて重要です.
陽子移転 (PT) や電子移転 (ET) などの反応メカニズムを理解することが鍵となる.
陽子電荷の位置が反応経路と産物形成に影響する.

研究の目的:

ガス相イオン/イオン反応におけるカチオン充電部位の影響を調査する.
競合する反応チャネルにおける製品分割を定量的に検討する.
電子移転解離 (ETD) と電子捕獲解離 (ECD) のメカニズムを解明する.

主な方法:

多重陽子モデルペプチドと単発アニオンを用いて.
PT,ET,ETD,および解離なしのET (ET,Dなし) チャンネルに製品の分割を分析する.
断片化パターンを比較し,バックボーンとサイドチェーン・ボンドの割れ目を比較する.

主要な成果:

陽子化されたライシン,アルギニン,ヒスティジンのペプチドカチオンは,固定電荷部位よりも高いETを示した.
プロトネートヒスティジンは最高ETを示し,Dは示されず,ライシン/アルギニンは完ぺきなET製品がなかった.
アルギニンカチオンは,最も多くのサイドチェーン損失をもたらし,ヒスティジンに続いて,ライシンが続いた.

結論:

陽子電荷の場所のアイデンティティと位置は,ETと断片化の経路に大きな影響を与えます.
アニオン反応物の同一性は,PTとサイドチェーン損失分数にも影響する.
観測されたETD/ECD製品には,複数のメカニズムが貢献し,充電部位と反応剤によって調節されます.

さらに関連する動画

11:04

Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides

Published on: September 7, 2019

16:11

Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry

Published on: June 8, 2022

関連する概念動画

02:48

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.

01:22

EDTA: Chemistry and Properties

Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...

01:09

Ion-Exchange Chromatography

Ion-exchange chromatography, or IEC, is a technique for separating ions based on their affinity for the stationary phase. The stationary phase is a cross-linked polymer resin with covalently attached ionic functional groups. The functional groups can be either positively charged (cation exchangers) or negatively charged (anion exchangers). A cation exchanger consists of a polymeric anion and active cations, while an anion exchanger is a polymeric cation with active anions. The choice of...

01:28

Ionic Association

The ionic association is the association of oppositely charged ions in an electrolyte solution to form ion pairs. Bjerrum defined ion pairs as two oppositely charged ions whose electrostatic attraction exceeds the thermal energy of the system, typically expressed as 2kT. Electrostatic attraction depends on ionic charge, separation distance, and the dielectric constant of the medium. Thermal energy, represented by kT, reflects the tendency of ions to move independently due to molecular motion.

01:17

Ion Exchange

Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...

02:58

Crystal Field Theory - Octahedral Complexes

Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...

関連する実験動画