3P-12 PDF
Identification of novel peptides from amphibian (Xenopus tropicalis) skin by direct tissue MALDI-MS analysis
Identification of novel peptides from amphibian (Xenopus tropicalis) skin by direct tissue MALDI-MS analysis
(AIST1, Kyoto Pref. Univ.2)
◯Y. Shigeri1, A. Yasuda1, Y. Hagihara1, K. Nishi2, K. Watanabe2, T. Imura1, H. Inagaki1, Y. Haramoto1, Y. Itou1, M. Asashima1
Keywords: MALDI, peptide, post-translational modification
Twelve novel peptides (Pxt-1 - 12) were isolated from the skin of X. tropicalis, using topological mass spectrometry analysis. Among them, Pxt-8, 9, and 10 were N-terminus of Pxt-1, N-terminus of Pxt-3, and C-terminus of Pxt-11, respectively. The Pxt-3 and 11 peptides shared significant sequence homologies with magainins 1, 2 and levitide, respectively. Pxt-12 was identical to the X. tropicalis XT-6-like precursor previously isolated. None of the Pxt peptides contained any Cys, Asp, Tyr or Trp. RT-PCR analysis confirmed the gene expressions of Pxt-2, Pxt-3, Pxt-4, Pxt-5, Pxt-7 and Pxt-11 in X. tropicalis skin. Several ion peaks corresponding to all identified Pxt peptides, were observed with MALDI-MS analysis of X. tropicalis secretory fluids, collected after in vivo stimulation which suggested that Pxt peptides were definitely secretory molecules. CD studies and the helical wheel projections suggested that Pxt-5, as well as mastoparan, at least, could form a typical amphiphilic alpha-helix.