1E06

Porcine Odorant Binding Protein Complexed with 5-methyl-2-(1-methylethyl)phenol

Summary for 1E06

• Entry DOI: 10.2210/pdb1e06/pdb
• Related: 1A3Y 1DZJ 1DZK 1DZM 1DZP 1E00 1E02
• Descriptor: ODORANT-BINDING PROTEIN, 5-METHYL-2-(1-METHYLETHYL)PHENOL (3 entities in total)
• Functional Keywords: odorant binding protein, lipocalins
• Biological source: SUS SCROFA (PIG)
• Total number of polymer chains: 2
• Total formula weight: 35743.26

Authors

Vincent, F.,Spinelli, S.,Cambillau, C.,Tegoni, M. (deposition date: 2000-03-10, release date: 2000-12-06, Last modification date: 2024-10-09)

Primary citation

Vincent, F.,Spinelli, S.,Ramoni, R.,Grolli, S.,Pelosi, P.,Cambillau, C.,Tegoni, M.
Complexes of Porcine Odorant Binding Protein with Odorant Molecules Belonging to Different Chemical Classes
J.Mol.Biol., 300:127-, 2000

PubMed Abstract: Porcine odorant binding protein (pOBP) is a monomer of 157 amino acid residues, purified in abundance from pig nasal mucosa. In contrast to the observation on lipocalins as retinol binding protein (RBP), major urinary protein (MUP) or bovine odorant binding protein (bOBP), no naturally occurring ligand was found in the beta-barrel cavity of pOBP. Porcine OBP was therefore chosen as a simple model for structure/function studies with odorant molecules. In competition experiments with tritiated pyrazine, the affinity of pOBP towards several odorant molecules belonging to different chemical classes has been found to be of the micromolar order, with a 1:1 stoichiometry. The X-ray structures of pOBP complexed to these molecules were determined at resolution between 2.15 and 1.4 A. As expected, the electron density of the odorant molecules was observed into the hydrophobic beta-barrel of the lipocalin. Inside this cavity, very few specific interactions were established between the odorant molecule and the amino acid side-chains, which did not undergo significant conformational change. The high B-factors observed for the odorant molecules as well as the existence of alternative conformations reveal a non-specific mode of binding of the odorant molecules in the cavity.

PubMed: 10864504
DOI: 10.1006/JMBI.2000.3820

Experimental method

X-RAY DIFFRACTION (2.12 Å)