The structure of the monomeric porcine odorant binding protein sheds light on the domain swapping mechanism.Spinelli, S., Ramoni, R., Grolli, S., Bonicel, J., Cambillau, C., Tegoni, M.
(1998) Biochemistry 37: 7913-7918
- PubMed: 9609684
- DOI: https://doi.org/10.1021/bi980179e
- Primary Citation of Related Structures:
- PubMed Abstract:
The X-ray structure of the porcine odorant binding protein (OBPp) was determined at 2.25 A resolution. This lipocalin is a monomer and is devoid of naturally occurring bound ligand, contrary to what was observed in the case of bovine OBP [Tegoni, M., et al. (1996) Nat. Struct. Biol. 3, 863-867; Bianchet, M. A., et al. (1996) Nat. Struct. Biol. 3, 934-939]. In this latter protein, a dimer without any disulfide bridges, domain swapping was found to occur between the beta- and alpha-domains. A single Gly (121) insertion was found in OBPp when it was compared to OBPb, which may prevent domain swapping from taking place. The presence of a disulfide bridge between the OBPp beta- and alpha-domains (cysteines 63 and 155) may lock the resulting fold in a nonswapped monomeric conformation. Comparisons with other OBPs indicate that the two cysteines involved in the OBPp disulfide bridge are conserved in the sequence, suggesting that OBPp may be considered a prototypic OBP fold, and not OBPb.
Architecture et Fonction des Macromolécules Biologiques, UPR 9039, CNRS, IFR1, Marseille, France.