1gm0
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(New page: 200px<br /><applet load="1gm0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1gm0" /> '''A FORM OF THE PHEROMONE-BINDING PROTEIN FROM...)
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Revision as of 14:02, 20 November 2007
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A FORM OF THE PHEROMONE-BINDING PROTEIN FROM BOMBYX MORI
Overview
Odorants are transmitted by small hydrophobic molecules that cross the, aqueous sensillar lymph surrounding the dendrites of the olfactory neurons, to stimulate the olfactory receptors. In insects, the transport of, pheromones, which are a special class of odorants, is mediated by, pheromone-binding proteins (PBPs), which occur at high concentrations in, the sensillar lymph. The PBP from the silk moth Bombyx mori (BmPBP), undergoes a pH-dependent conformational transition between the forms, BmPBP(A) present at pH 4.5 and BmPBP(B) present at pH 6.5. Here, we, describe the NMR structure of BmPBP(A), which consists of a tightly packed, arrangement of seven alpha-helices linked by well defined peptide segments, and knitted together by three disulfide bridges. A scaffold of four, alpha-helices that forms the ligand binding site in the crystal structure, of a BmPBP-pheromone complex is preserved in BmPBP(A). The C-terminal, dodecapeptide segment, which is in an extended conformation and located on, the protein surface in the pheromone complex, forms a regular helix, alpha(7), which is located in the pheromone-binding site in the core of, the unliganded BmPBP(A). Because investigations by others indicate that, the pH value near the membrane surface is reduced with respect to the bulk, sensillar lymph, the pH-dependent conformational transition of BmPBP, suggests a novel physiological mechanism of intramolecular regulation of, protein function, with the formation of alpha(7) triggering the release of, the pheromone from BmPBP to the membrane-standing receptor.
About this Structure
1GM0 is a Single protein structure of sequence from Bombyx mori. Full crystallographic information is available from OCA.
Reference
NMR structure reveals intramolecular regulation mechanism for pheromone binding and release., Horst R, Damberger F, Luginbuhl P, Guntert P, Peng G, Nikonova L, Leal WS, Wuthrich K, Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14374-9. Epub 2001 Nov 27. PMID:11724947
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