Synthetic peptide mimicking of binding sites on olfactory receptor proteinfor use in 'electronic nose'

A putative tertiary structure model of the dog's olfactory receptor (olfd c anfa) is established in this study. By using a target odorous compound (tri methylamine), it is possible to locate the most plausible binding sites bet ween the receptor model structure and the target odorous molecules through computer docking simulations. The two short oligo-peptide sequences (orp61 and orp188) for trimethylamine sensing were identified, synthesized, purifi ed and coated onto the surface of the separate piezoelectric gold electrode s. These two peptides show a high binding capability for trimethylamine. To further enhance the sensitivity of the polypeptides towards the target com pound, the polarity and the degree of docking were changed by a site-specif ic modification technique. The orp61 sequence was modified by substituting two amino acids in the binding pocket resulting in 33% increase in sensitiv ity towards trimethylamine and reduced noises from other non-target chemica ls. The techniques used in the present study offer a unique approach for sy nthesizing peptides in mimicking binding domain of olfactory receptors. The approach can be easily applied to further development of recognized molecu les for gas sensing, especially for use in 'electronic noses'. (C) 2000 Els evier Science B.V. All rights reserved.