Structural comparison of central and peripheral mouse MUPs

Phelan MM, McLean L, Hurst JL, Beynon RJ, Lian LY. (2014)Comparative study of the molecular variation between 'central' and 'peripheral' MUPs and significance for behavioural signalling.

MUPs (major urinary proteins) play an important role in chemical signalling in
rodents and possibly other animals. In the house mouse (Mus musculus domesticus)
MUPs in urine and other bodily fluids trigger a range of behavioural responses
that are only partially understood. There are at least 21 Mup genes in the
C57BL/6 mouse genome, all located on chromosome 4, encoding sequences of high
similarity. Further analysis separates the MUPs into two groups, the 'central'
near-identical MUPs with over 97% sequence identity and the 'peripheral' MUPs
with a greater degree of heterogeneity and approximately 20-30% non-conserved
amino acids. This review focuses on differences between the two MUP sub-groups
and categorizes these changes in terms of molecular structure and pheromone
binding. As small differences in amino acid sequence can result in marked changes
in behavioural response to the signal, we explore the potential of single amino
acid changes to affect chemical signalling and protein stabilization. Using
analysis of existing molecular structures available in the PDB we compare the
chemical and physical properties of the ligand cavities between the MUPs.
Furthermore, we identify differences on the solvent exposed surfaces of the
proteins, which are characteristic of protein-protein interaction sites.
Correlations can be seen between molecular heterogeneity and the specialized
roles attributed to some MUPs.