Collision-Induced Dissociation Analysis of Brevianamide A and C in Electrospray Ionization Mass Spectrometry

• Autor(a) principal: Oliveira,Ana Lígia L. de
• Data de Publicação: 2015
• Outros Autores: Vessecchi,Ricardo, Lopes,Norberto P., Debonsi,Hosana M.
• Tipo de documento: Relatório
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532015000400822
• topic: diketopiperazine; fragmentation mechanisms; brevianamide; natural products

Brevianamides A and C are isomeric cyclic peptides with several reported biological activities, isolated from diverse microorganisms. Currently, there has been no previous investigation of brevianamide fragmentation utilizing electrospray ionization mass spectrometry (ESI-MS). In this work experiments were carried out in the positive mode using two different spectrometers (low and high resolution) with an ESI source. Computational chemistry studies helped identify the protonation sites based upon atomic charges, proton affinities and molecular orbitals, computed using the B3LYP/6-31++G (d,p) model. The data suggests that the presence of the allylic position of the lactamic N in brevianamides C governs its fragmentation pathways. Distinguishing between brevianamides A and C using positive ion electrospray tandem mass spectrometry (ESI(+)MS/MS) is made possible by the spectral difference of each isomer and offers an alternative to other spectroscopic techniques.