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PLoS One

Title:		A lysine at the C-terminus of an odorant-binding protein is involved in binding aldehyde pheromone components in two Helicoverpa species
Author(s):		Sun YL; Huang LQ; Pelosi P; Wang CZ;
Address:		"State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China"
Journal Title:		PLoS One
Year:		2013
Volume:		20130125
Issue:		1
Page Number:		e55132 -
DOI:		10.1371/journal.pone.0055132
ISSN/ISBN:		1932-6203 (Electronic) 1932-6203 (Linking)
Abstract:		"Odorant-binding proteins (OBPs) are soluble proteins, whose role in olfaction of insects is being recognized as more and more important. We have cloned, expressed and purified an OBP (HarmOBP7) from the antennae of the moth Helicoverpa armigera. Western blot experiments indicate specific expression of this protein in the antennae of adults. HarmOBP7 binds both pheromone components Z-11-hexadecenal and Z-9-hexadecenal with good affinity. We have also performed a series of binding experiments with linear aldehydes, alcohols and esters, as well as with other compounds and found a requirement of medium size for best affinity. The affinity of OBP7, as well as that of a mutant lacking the last 6 residues does not substantially decrease in acidic conditions, but increases at basic pH values with no significant differences between wild-type and mutant. Binding to both pheromone components, instead, is negatively affected by the lack of the C-terminus. A second mutant, where one of the three lysine residues in the C-terminus (Lys123) was replaced by methionine showed reduced affinity to both pheromone components, as well as to their analogues, thus indicating that Lys123 is involved in binding these compounds, likely forming hydrogen bonds with the functional groups of the ligands"
Keywords:		"Aldehydes/*metabolism Amino Acid Sequence Animals Kinetics Ligands Lysine/*chemistry Models, Molecular Molecular Sequence Data Moths/*metabolism Mutation Pheromones/*metabolism Protein Binding Protein Conformation Receptors, Odorant/*chemistry/genetics/*m;"
Notes:		"MedlineSun, Ya-Lan Huang, Ling-Qiao Pelosi, Paolo Wang, Chen-Zhu eng Research Support, Non-U.S. Gov't 2013/02/02 PLoS One. 2013; 8(1):e55132. doi: 10.1371/journal.pone.0055132. Epub 2013 Jan 25"