Comparative evaluation of five protocols for protein extraction from stony corals (Scleractinia) for proteomics.

Corals especially the reef-building species are very important to marine ecosystems. Proteomics has been used for researches on coral diseases, bleaching and responses to the environment change. A robust and versatile protein extraction protocol is required for coral proteomics. However, a comparative evaluation of different protein extraction protocols is still not available for proteomic analysis of stony corals. In the present study, five protocols were compared for protein extraction from stony corals. The five protocols were TRIzol, phenol-based extraction (PBE), trichloroacetic acid (TCA)-acetone, glass bead-assisted extraction (GBAE) and a commercially available kit. PBE, TRIzol and the commercial kit were more robust for extracting proteins from stony corals. The protein extraction efficiency and repeatability, two dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS) were employed to evaluate the protocols. The results indicated that PBE protocol had the better protein extraction efficiency than the others. Protein extraction coverage varied among the procedures. Each protocol favored for certain proteins. Therefore, it is very important for coral proteomic analysis to select a suitable protein protocol upon the experimental design. In general, PBE protocol can be the first choice for extracting proteins from stony corals.