RESUMO
Isotope-coded affinity tags (ICATs) are valuable tools for mass spectrometry-based quantitative proteomics, in particular, for comparison of protein (cysteine-residue) thiol oxidation state in normal, stressed, and diseased tissue. However, the iodoacetamido electrophile used in most commercial ICATs suffers from poor thiol-selectivity and modest rates of adduct formation, which can lead to spurious results. Hence, we designed and synthesized three ICATs containing thiol-selective N-alkylmaleimide electrophiles (isotope-coded maleimide affinity tags = ICMATs) and assessed these as mass spectrometry probes for ratiometric analysis of lysozyme and muscle proteomes. Two ICMAT pairs containing butylene/D8-butylene linkers were effective MS probes, but not ideal for typical proteomics workflows, because peptides bearing these tags frequently did not coelute with HPLC. A switch to a phenylene/13C6-phenylene linker solved this issue without compromising the efficiency of adduct formation.
Assuntos
Isótopos de Carbono/química , Marcação por Isótopo/métodos , Maleimidas/química , Proteínas Musculares/metabolismo , Proteômica/métodos , Animais , Cromatografia Líquida , Cães , Regulação da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos mdx , Modelos Moleculares , Proteínas Musculares/química , Proteínas Musculares/genética , Músculo Esquelético , Conformação Proteica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em TandemRESUMO
The first approaches to the 10'-anthronyl-2-anthraquinone skeleton have been devised, allowing two syntheses of the marine natural product albopunctatone. Both routes involve regioselective addition of a nucleophilic masked anthraquinone to a protected chrysazin derivative; the best affords albopunctatone in five steps and 35% overall yield. Albopunctatone exhibits potent inhibitory activity against Plasmodium falciparum and negligible toxicity to a range of other microbial pathogens and mammalian cells.
