OBP sequence logo and three-dimensional structure. (a) Degree of amino acid sequence conservation  along the odorant-binding protein (OBP) sequences in phylogenetic subfamilies II and III. The locations of the α-helices were determined by homology with LUSH (DmelObp76a gene from OBP subfamily III). α-Helices are depicted as cylinders and beta sheets as bold arrows. (b) Three-dimensional structure of the LUSH Protein (PDB ID: 1OOI) , visualized using the Molecular Biology Toolkit platform . The color ramp ranges from blue (amino-terminal) to red (carboxyl-terminal).