RESUMO
Resistance is (not) futile: The yatakemycin biosynthetic gene cluster involves the ytkR2 gene, which encodes a protein with homology to a recently discovered bacterial DNA glycosylase. Genetic validation inâ vivo, biochemical assays, and inâ vitro mutagenesis studies revealed that YtkR2 confers resistance for the bacteria by specifically recognizing and cleaving the YTM-modified base (see scheme).
Assuntos
Antibióticos Antineoplásicos/farmacologia , DNA Glicosilases/metabolismo , Reparo do DNA , Indóis/metabolismo , Pirróis/metabolismo , Sequência de Aminoácidos , Bacillus cereus/genética , Bacillus cereus/metabolismo , Sequência de Bases , Clonagem Molecular , Dano ao DNA , DNA Glicosilases/genética , Resistencia a Medicamentos Antineoplásicos , Duocarmicinas , Indóis/análise , Modelos Moleculares , Dados de Sequência Molecular , Pirróis/análise , Streptomyces/genética , Streptomyces/metabolismoRESUMO
This review focuses on recent applications of matrix-assisted laser desorption ionization-Fourier-transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS) in qualitative and quantitative analysis of low molecular weight compounds. The scope of the work includes amino acids, small peptides, mono and oligosaccharides, lipids, metabolic compounds, small molecule phytochemicals from medicinal herbs and even the volatile organic compounds from tobacco. We discuss both direct analysis and analysis following derivatization. In addition we review sample preparation strategies to reduce interferences in the low m/z range and to improve sensitivities by derivatization with charge tags. We also present coupling of head space techniques with MALDI-FTICR-MS. Furthermore, omics analyses based on MALDI-FTICR-MS were also discussed, including proteomics, metabolomics and lipidomics, as well as the relative MS imaging for bio-active low molecular weight compounds. Finally, we discussed the investigations on dissociation/rearrangement processes of low molecular weight compounds by MALDI-FTICR-MS.
Assuntos
Metabolômica/métodos , Proteômica/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Análise de Fourier , Metabolômica/instrumentação , Peso Molecular , Proteômica/instrumentação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/instrumentaçãoRESUMO
The gas-phase synthesis of hydrodiphenylcyclopropenylium from alkali-cationized alpha,alpha'-dibromodibenzyl ketone (1) via nonclassical Lewis-acid-induced Favorskii rearrangement has been studied by electrospray ionization/tandem mass spectrometry (ESI-MS/MS) and theoretical methods, showing that cations [1-Br](+) by debromination from 1 and 1.M(+)(M = Li or Na) by alkali-metal cationization of 1 could convert into the protonated diphenylcyclopropenone 2.H(+) by collision-induced dissociation in the gas phase. A concerted mechanism for the Lewis-acid-induced Favorskii rearrangement from alkali-metal-cationized alpha,alpha'-dibromodibenzyl ketone was proposed and studied, based on mass spectrometric results and theoretical methods.