1e02: Difference between revisions

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.

1E02 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with UNA as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Sites: AC1 and AC2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1E02 OCA].  

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