title: Isolation and sequence analysis of peptides from the skin secretion of the Middle East tree frog Hyla savignyi.
abstract: Novel peptides were identified in the skin secretion of the tree frog Hyla savignyi. Skin secretions were collected by mild electrical stimulation. Peptides were separated by reversed-phase high-performance liquid chromatography. Mass spectra were acquired by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), and fragment ion spectra were obtained after collision-induced dissociation and electron capture dissociation. Peptides were analyzed by manual de novo sequencing and composition-based sequencing (CBS). Sequence analyses of three so far undescribed, structurally unrelated peptides are presented in this paper, having the sequences DDSEEEEVE-OH, P*EEVEEERJK-OH, and GJJDPJTGJVGGJJ-NH(2). The glutamate-rich sequences are assumed to be acidic spacer peptides of the prepropeptide. One of these peptides contains the modified amino acid hydroxyproline, as identified and localized by high-accuracy FTICR-MS. Combination of CBS and of experience-based manual sequence analysis as complementary and database-independent sequencing strategies resulted in peptide identification with high reliability.
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Justus Liebig University, 35392 Schubertstr. 60, Bldg. 16, Giessen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Langsdorf
authors.forename: Alireza
authors.initials: A
authors.lastname: Ghassempour
authors.forename: Andreas
authors.initials: A
authors.lastname: Römpp
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spengler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D020539:Sequence Analysis, Protein; D012867:Skin / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D010455:Peptides