Structure and biotechnological applications of odorant-binding proteins

Abstract

Odorant-binding proteins (OBPs) are small soluble polypeptides found in sensory organs of vertebrates and insects as well as in secretory glands and are dedicated to detection and release of chemical stimuli. OBPs of vertebrates belong to the family of lipocalin proteins, while those of insects are folded into α-helical domains. Both types of architectures are extremely stable to temperature, organic solvents and proteolytic digestion. These characteristics make OBPs suitable elements for fabricating biosensors to be used in the environment, as well as for other biotechnological applications. The affinity of OBPs for small volatile organic compounds is in the micromolar range, and they have broad specificity to a range of ligands. For biotechnological applications, OBPs can be expressed in bacterial systems at low cost and are easily purified. The large amount of information available on their structures and affinities to different molecules should allow the design of specific mutants with desired characteristics and represent a solid base for tailoring OBPs for different applications.

Olfactory biosensor for insect semiochemicals analysis by impedance sensing of odorant-binding proteins on interdigitated electrodes

“…These soluble binding proteins, which are mainly odorant-binding proteins (OBPs), not only can be expressed and purified easily, but also are highly stable to temperature, pH, solvents and proteases (Wei et al, 2008;Pelosi et al, 2014;Lu et al, 2014). With these excellent properties, biosensors based on mammal OBPs, such as bovine OBP and porcine OBP, had already been studied for detection of ethanol, octenol, and carvone, and obtained high specificity and sensitivity (Hou et al, 2005;Ramoni et al, 2007;Capone et al, 2009;Pietrantonio et al, 2013).…”

Smell Sensors Based on Odorant Binding Proteins

“…Generally, the tested frequency was set from 1 Hz to 100 kHz with a 5 mV alternating voltage. Odorants at different concentrations were added to the plate wells containing 5 mMK 4 [Fe(CN) 6 ]/K 3 [Fe(CN) 6 ] (1:1). All of impedance detecting was performed at room temperature (18-25 °C).…”

“…However, their structures have their own characteristics. Vertebrate OBPs belong to a subclass of lipocalins and share a conserved folding pattern, such as eight antiparallel β-sheet and an α-helix at the C-terminal end [6,7]. Meanwhile, vertebrate OBPs exist as monomer or homodimer depending on OBPs.…”

Chemosensory proteins involved in host recognition in the stored‐food mite Tyrophagus putrescentiae

“…19,20 Many studies have used homology modelling in structure-based drug discovery; however, only a few CSP modelling studies have been performed in insects. 21,22 Mites have no eyes or antennae, and they explore the environment mainly through their tactile and chemical senses. The mites utilise the olfactory system to gain semiochemicals under natural conditions, and then guide their behaviour.…”