ガス状ペプチドイオンをN-ヒドロキシスクシニミドエステル反応剤イオンで共振的に改変する
Marija Mentinova1, Scott A McLuckey
1Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
Journal of the American Chemical Society
|December 7, 2010
まとめ
ペプチドのガス相共性改変は,N-ヒドロキシスッキニミド (NHS) エステルを使用して達成されます. このイオン/イオン反応により,選択的なアミン群改変が可能になり,これはプロテオミクスや化学生物学の応用において極めて重要です.
科学分野:
- アナリティカル・ケミストリー (Analytical Chemistry) とは
- 化学生物学 化学生物学とは
- マススペクトロメトリーによる質量スペクトロメトリーです.
背景:
- ペプチドの選択的改変は,構造的および機能的分析に不可欠です.
- ガス相イオン/イオン反応は,化学的変換のためのユニークな環境を提供します.
- N-hydroxysuccinimide (NHS) エステルは,溶液中のアミンの改変のために広く使用される反応剤です.
研究 の 目的:
- NHSエステルを用いて,ガス相ポリペプチドにおけるプライマリアミン群の共性変異を実証する.
- ペプチドによるNHSエステル媒介イオン/イオン反応のメカニズムと特性を調査する.
- ガス状ペプチドおよびタンパク質の選択的化学誘導の可能性を調査する.
主な方法:
- ペプチド分析イオンとNHSまたはスルフォ-NHS反応剤の間のイオン/イオン反応を利用する.
- イオン活性化を用い,共振変異を誘導し,反応産物を分析する.
- ニュートラルなNHS/硫黄-NHS損失を観察し,その後の断片イオン分析によって修正の特徴づけ.
主要な成果:
- 耐久性の高いペプチド-反応剤複合体の形成は,共振変異の前提条件である.
- イオン活性化により,中性なNHS/硫黄-NHS分子が失われ,アミド結合が形成されます.
- 修正は主にライシン側鎖のアミン群で発生し,N末端の関与は最小限である.
- 改変を含む配列情報断片イオンが生成されます.
結論:
- NHSの反応剤を用いたプライマリアミンのガス相共性改変は可能である.
- この方法により,様々な化学群をガス状ペプチドやタンパク質に結合させることができます.
- このアプローチは,質量スペクトロメトリーベースのプロテオミクスの選択的誘導のための強力なツールを提供します.
関連する概念動画
01:29Preparation of Amides
Amides are synthesized by treating carboxylic acids with amines in the presence of dehydrating agents like dicyclohexylcarbodiimide (DCC).
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
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...
02:43Peptide Bonds
A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid's carboxyl group and another amino acid's amino group combine, releasing a water molecule. The resulting bond is the peptide bond. The products that such linkages form are peptides. As more amino acids join this growing chain, the resulting chain is a polypeptide. Each polypeptide has a free amino group at one end. This end has the N-terminal, or the amino-terminal, and the other end has a free...
01:19α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
The pinacol and McMurry reactions involve the reductive coupling of ketones or aldehydes. Similarly, the bimolecular reductive coupling of two ester molecules in the presence of sodium metal in an aprotic solvent yields an α-hydroxy ketone product. The α-hydroxy ketone is also called acyloin, so the reaction is referred to as ‘acyloin condensation.’