| Title: | Molecular switches for pheromone release from a moth pheromone-binding protein |
| Address: | "Maeda-Duffey Laboratory, Department of Entomology, University of California, 1 Shields Avenue, Davis, CA 95616, USA" |
| Journal Title: | Biochem Biophys Res Commun |
| DOI: | 10.1016/j.bbrc.2008.05.087 |
| ISSN/ISBN: | 1090-2104 (Electronic) 0006-291X (Linking) |
| Abstract: | "Pheromone-binding proteins (PBPs) are involved in the uptake of pheromones from pores on the antennae, transport through an aqueous environment surrounding the olfactory receptor neurons, and fast delivery to pheromone receptors. We tested the hypothesis that a C-terminal segment and a flexible loop are involved in the release of pheromones to membrane-bound receptors. We expressed in Escherichia coli 11 mutants of the PBP from the silkworm moth, BmorPBP, taking into consideration structural differences between the forms with high and low binding affinity. The N-terminus was truncated and His-69, His-70 and His-95 at the base of a flexible loop, and a cluster of acidic residues at the C-terminus were mutated. Binding assays and circular dichroism analyses support a mechanism involving protonation of acidic residues Asp-132 and Glu-141 at the C-terminus and histidines, His-70 and His-95, in the base of a loop covering the binding pocket. The former leads to the formation of a new alpha-helix, which competes with pheromone for the binding pocket, whereas positive charge repulsion of the histidines opens the opposite side of the binding pocket" |
| Keywords: | Amino Acid Sequence Animals Carrier Proteins/biosynthesis/*chemistry/genetics DNA Mutational Analysis Escherichia coli/genetics Fatty Alcohols/*chemistry Hydrogen-Ion Concentration Insect Proteins/biosynthesis/*chemistry/genetics Intercellular Signaling P; |
| Notes: | "MedlineXu, Wei Leal, Walter S eng Research Support, U.S. Gov't, Non-P.H.S. 2008/05/28 Biochem Biophys Res Commun. 2008 Aug 8; 372(4):559-64. doi: 10.1016/j.bbrc.2008.05.087. Epub 2008 May 27" |
