tailieunhanh - Báo cáo khoa học: Crystal structures of bovine odorant-binding protein in complex with odorant molecules

The structure of bovine odorant-binding protein (bOBP) revealed astrikingfeature ofadimerformed bydomain swapping 2 [Tegoni, M., Ramoni, R., Bignetti, E., Spinelli, S. & Cambillau, C. (1996)Nat. Struct. , 863–867; Bian-chet, ., Bains, G., Pelosi, P., Pevsner, J., Snyder, ., Monaco, . & Amzel, . (1996)Nat. Struct. , 934–939] and the presence of a naturally occuring ligand [Ramoni, R., Vincent, F., Grolli, S., Conti, V., Malosse, C., Boyer, ., Nagnan-Le Meillour, P., Spinelli, S., Cambil-lau, C. & Tegoni, M. (2001)J. Biol. , 7150–7155]. These features led us to investigate the binding of odorant molecules with bOBP in solution and in the crystal | Eur. J. Biochem. 271 3832-3842 2004 FEBS 2004 doi Crystal structures of bovine odorant-binding protein in complex with odorant molecules Florence Vincent1 Roberto Ramoni2 Silvia Spinelli1 Stefano Grolli2 Mariella Tegoni1 and Christian Cambillau1 1 Architecture et Fonction des Macromolecules Biologiques UMR 6098 CNRS Marseille France 2Dipartimento di Produzioni Animali Biotecnologie Veterinarie Qualita e Sicurezza degli Alimenti U niversiia di Parma Parma Italy The structure of bovine odorant-binding protein bOBP revealed a striking feature of a dimer formed by domain swapping Tegoni M. Ramoni R. Bignetti E. Spinelli S. Cambillau C. 1996 Nat. Struct. Biol. 3 863-867 Bian-chet . Bains G. Pelosi P. Pevsner J. Snyder . Monaco . Amzel . 1996 Nat. Struct. Biol. 3 934-939 and the presence of a naturally occuring ligand Ramoni R. Vincent F. Grolli S. Conti V. Malosse C. Boyer . Nagnan-Le Meillour P. Spinelli S. Cambil-lau C. Tegoni M. 2001 J. Biol. Chern. 276 7150-7155 . These features led us to investigate the binding of odorant molecules with bOBP in solution and in the crystal. The behavior of odorant molecules in bOBP resembles that observed with porcine OBP pOBP although the latter is monomeric and devoid of ligand when purified. The odorant molecules presented Kd values with bOBP in the micromolar range. Most of the X-ray structures revealed that odorant molecules interact with a common set of residues forming the cavity wall and do not exhibit specific interactions. Depending on the ligand and on the monomer A or B a single residue - Phe89 - presents alternate conformations and might control cross-talking between the subunits. Crystal data on both pOBP and bOBP in contrast with binding and spectroscopic studies on rat OBP in solution reveal an absence of significant conformational changes involving protein loops or backbone. Thus the role of OBP in signal triggering remains unresolved. Keywords crystal structure domain