Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/23/2011
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Peptides play significant roles in physiology as hormones, neurotransmitters, growth, antimicrobial, and signal transducing factors. Identification of their tissue specific occurrence and abundance may lead to a better understanding of their physiological significance. Previously, we identified mature forms of defensins and thymosin beta peptides from chicken and turkey white blood cells by direct MALDI-TOF-MS (matrix assisted laser desorption ionization-time-of-flight mass spectrometry). This reinforces the contention that MS approach may be a suitable platform to identify other cell and tissue associated peptides in their mature forms. As a proof of concept, we sought to find homologous avian beta defensin 2 (AvBD2) peptides from pheasant and quail using purified heterophils and the methanol/ acetic acid extract of bone marrow. Based on the pattern of their spectra and comparisons with chicken and turkey tissue profiles, the spectra corresponding to m/z 4114 and 4164 were tentatively identified as possible defensins of pheasant and quail respectively. MALDI-TOF-MS spectra obtained after reducing and alkylating with iodoacetamide confirmed them as AvBD due to the exact mass shift by 348 Da indicative of three disulfide bonds that are characteristics of beta defensins. The carbamidomethylated products were purified by reverse phase HPLC and subjected to trypsin digestion. In Source-, and Post Source Decay fragmentations were done to establish structural information by comparing them with known sequences of chicken and turkey AvBD2 from Genbank data. These results suggest that MS based approach can be extended to identify and characterize not only the homologous but also other novel peptides and understand their significance.