MUP ligand binding

Robertson, D.H.L., Marie, A.D., Veggerby, C., Hurst, J.L. & Beynon, R.J. (2001) Characteristics of ligand binding and release by major urinary proteins. . In: Chemical Signals in Vertebrates (Ed. A. Marchlewska-Koj, D. Muller-Schwarze & J. Lepri) pp169-176. Plenum Press, New York.

The major urinary proteins (MUPs), found abundantly in mouse urine, have heterogeneous primary structures and are associated with a number of endogenous ligands. Two of these, 3,4-dehydro-exo-brevicomin (brevicomin) and 2-sec-butyl-4,5-dihydrothiazole (thiazole) are well characterised mouse pheromones. One function of MUPs is to prolong olfactory signals in the time domain by slowly releasing brevicomin and thiazole. This study uses a novel technique to investigate the characteristics of thiazole and brevicomin loss from MUPs in deposited urine. The loss of these ligands occurs in two distinct phases, the rates and proportions of which are reported. The binding behaviour of N-phenyl napthylamine (NPN), a fluorescent reporter ligand, towards four MUPs, with known amino-acid sequences, has allowed the effect of MUP heterogeneity on the ligand-binding cavity to be assessed. Variation at one position in the peptide chain has a significant effect on the properties of the ligand-binding cavity.