Mass spectrometric study of peptides secreted by the skin glands of the brown frog Rana arvalis from the Moscow region

Abstract

A high-performance liquid chromatography nano-electrospray ionization Fourier transform mass spectrometry (HPLC/nanoESI-FTMS) approach involving recording of collision-activated dissociation (CAD) and electron-capture dissociation (ECD) spectra of an intact sample and two its modifications after performic oxidation and reduction followed by carboxamidomethylation helps to establish peptide profiles in the crude secretion of frog species at mid-throughput level, including de novo sequencing. The proposed derivatization procedures allow increasing of the general sequence coverage in the backbone, providing complementary information and, what is more important, reveal the amino acid sequence in the cystine ring ('rana box'). Thus purely mass spectrometric efficient sequencing becomes possible for longer than usual proteolytic peptides. Seventeen peptides belonging to four known families were identified in the secretion of the European brown frog Rana arvalis inhabiting the Moscow region in Russia. Ranatuerins, considered previously a unique feature of the North American species, as well as a new melittin-related peptide, are worth special mention. The developed approach was previously successfully used for the identification of peptides in the skin secretion of the Caucasian green frog Rana ridibunda.

Mass spectrometric analysis of peptides from an immobilized lipase: focus on oxidative modifications

“…The sequence coverage could be increased further by as much as 25% by the use of β ‐me prior to protease digestion. Cysteine residues were found only when β ‐me treatment was included, which was expected since disulfide bridges are scarcely seen in MS 22. Combining the treatment with the two proteases and reduction with β ‐me resulted in identification of 92% of the lipase sequence (Figs.…”

Mass spectrometric study of bradykinin‐related peptides (BRPs) from the skin secretion of Russian ranid frogs

“…The bradykinin‐related peptides isolated from the skin secretions of Russian ranid frogs are listed in Table . The compositions of the skin secretions of four Russian frog species included in the current investigation ( R. ridibunda , R. lessonae , R. arvalis , R. temporaria ) have been published previously . The present study contains augmented and specific information concerning the BRPs from the mentioned species.…”

Antimicrobial peptides from the skin of the Asian frog, Odorrana jingdongensis: De novo sequencing and analysis of tandem mass spectrometry data

“…It is impossible to discriminate the isobaric I/L based on the data of the low energy CID MS/MS [17]; it could be achieved by the high energy collision-induced dissociation (HCD) MS/MS; however, the characteristic losses fragment ions (d or w ions) for the discrimination of I/L in HCD are not commonly observed [30,39,48,49]. Thus, it has been accepted to assign I/L indirectly based on the known sequences of the cDNA clones in the same species [29,50] or on the known sequences of analogues in the same or others species [39,48,49]. This assignment in our study is based on the interspecific distribution of the identical AMPs is common in this genus as described above.…”