Structure-based ligand binding sites of protein p14.5, a member of protein family YER057c/YIL051c/YjgF.

Seventeen mutants with one, two or three amino acids substitutions of human protein p14.5, homologue to well-known tumor antigen from goat liver UK114 and a member of proteins YER057c/YIL051c/YjgF family, have been used for structure-functional relation studies and ligand binding analysis using cross-linking by triacryloyl-hexahydro-s-triazine (TAT), size exclusion chromatography, free fatty acid and 8-anilino-1-naphthalenesulfonic acid (ANS) binding assays. Amino acids having the most significant impact on the ligand binding activity have been determined: R107, N93, Y21 and F89. Arginine 107 has been identified as the most accessible amino acid in the cleft. Trimeric structure of protein p14.5 has been confirmed as being essential for stoichiometric small ligand binding activity and oligomeric structure of p14. Ligand binding activity may be related with the biological functions of these proteins, which still are not understood well.