Sequence Analysis of the Full-length cDNA and Protein Structure Homology Modeling of FABP2 from Paralichthys Olivaceus.

Using zebrafish intestinal fatty acid-binding protein 2 (FABP2) mRNA sequence as the initial query probe, four highly homologous Paralichthys olivaceus EST sequences were retrieved from Genbank database. The assembled full-length cDNA contains the open reading frame of P. olivaceus FABP2 gene, which was validated by subsequent RT-PCR cloning. In the coding region, the average GC content is 56%, but it would reach 76.8% if only counting for the third base of the codons. The deduced P. olivaceus FABP2 polypeptide contains 132 amino acids (aa), with a predicted molecular size of 15.3 kD and pI at 6.74. This protein multiple-alignment has shown that this peptide is 75.7% identical to the corresponding homologous protein in Danio rerio. Among the 7 aa that are essential for FABP2 function, 3 were found to be conserved among P. olivaceus, Danio rerio, Tetraodon nigroviridi, Rattus norvegicus, and Homo sapiens. The study provides essential information on molecular evolution and function of FABP family.