In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 25 ( 2001-12-04), p. 14374-14379
Kurzfassung:
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 α-helices linked by well defined peptide segments and knitted together by three disulfide bridges. A scaffold of
four α-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, α 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 α 7 triggering
the release of the pheromone from BmPBP to the membrane-standing receptor.
Materialart:
Online-Ressource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.251532998
Sprache:
Englisch
Verlag:
Proceedings of the National Academy of Sciences
Publikationsdatum:
2001
ZDB Id:
209104-5
ZDB Id:
1461794-8
SSG:
11
SSG:
12
