1GM6: 3-D Structure Of A Salivary Lipocalin From Boar

The X-ray structure of variant A of authentic boar salivary lipocalin (SAL), a pheromone-binding protein specifically expressed in the submaxillary glands of the boar, has been solved and refined at 2.1 A resolution. The structure displays a classical lipocalin fold with a nine-stranded sandwiched beta barrel and an alpha helix. A putative glycosylation site, at position 53, has been found to carry a GlcNAc sugar residue. In contrast with what was expected on the basis of mass spectroscopy reports, the internal cavity was found to be devoid of bound pheromonal compound (androstenone or androstenol). Instead, a small electron density volume could be satisfied by a glycerol molecule, a component of the cryoprotecting liquor. The internal cavity was revealed to be very small for steroid compound accommodation. Therefore, docking and molecular dynamics experiments were performed with both pheromonal compounds. These simulations clearly demonstrate a volume increase of the cavity upon steroid binding and the adaptation of the amino-acid side chains to the steroid molecules. This explains the higher affinity of SAL for both steroid molecules compared to other smaller molecules, although no specific interaction is established with either compound.
PDB ID: 1GM6Download
MMDB ID: 19393
PDB Deposition Date: 2001/9/11
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.13  Å
Source Organism:
Similar Structures:
Biological Unit for 1GM6: monomeric; determined by author and by software (PISA)
Molecular Components in 1GM6
Label Count Molecule
Protein (1 molecule)
Salivary Lipocalin(Gene symbol: SAL1)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB