Sequence And Structural Searches For An Activation Mechanism

The conventional view of ligand-induced allosteric regulation of G protein activation assumes some form of TM helix movement, involving some combination of trans-lational or rotational movement, in whichever plane, and by bending, extension or uncoiling of a helix. Being able to capture this "activation" event would provide a desirable read-out of agonist activity and might also distinguish between other flavors of partial or inverse agonism, allosteric modulation, and antagonism.

The conserved sequence features of the rhodopsin family members are mapped onto the known rhodopsin structure to aid in the search of a putative activation mechanism. Apart from the obviously serpentine form and the S-S bridge, the highly conserved TM3 DRY and TM7 NPxxY motifs are the only other regions of particular interest (Figure 10.4C).

0 0

Post a comment