Table 3.

Distances between Positions of Fluorescence Donors within CCK and Fluorescence Acceptors within the CCK Receptor in Two Contrasting Published Molecular Models^a

	model 1 photoaffinity labeling (10)			model 2 receptor mutagenesis (11)
	R, Å
CCK position	24	29	33	25b	29	33
Receptor 94 position	24.0	22.8	21.0	26.9	19.6	12.9c
Receptor 102 position	14.2	12.8	16.2	17.3	15.4	16.8
Receptor 204 position	28.0	24.0	25.8	32.3	26.2	24.4
Receptor 341 position	13.4	14.2	15.7	20.0	14.9	19.0c

^aNote: distances measured from C_β of the residue within CCK to the C_β of the corresponding receptor residue, except when the residue is a glycine, at which time C_α was utilized in the measurement.

^bThere is no residue in position 24 in this model: therefore, the position 25 residue was utilized as an approximation for this measurement.

^cMarks distances outside of the 95% confidence interval that includes the distances determined in the FRET analysis.