Table 2.

Comparison of ligand-associated spectral shifts of acrylodan covalently attached at one of five positions in mAChE with ligand-associated variability of B factors observed from X-ray structures.

Ligand	Leu 76 (Gln 74) Ω Loop gorge rim			Glu 81 (Ser 79) Ω Loop top outside			Glu 84 (Glu 82) Ω Loop top outside			Tyr 124 (Tyr 121) Gorge “choke point”			His 287 (Asn 280) Acyl pocket loop, PAS
	Spectral shift (nm)	Δ B value (complex-apo)		Spectral shift (nm)	Δ B value (complex-apo)		Spectral shift (nm)	Δ B value (complex-apo)		Spectr al shift (nm)	Δ B value (complex-apo)		Spectral shift (nm)	Δ B value (complex-apo)
	mAChE	m,hAChE	TcAChE	mAChE	m,hAChE	TcAChE	mAChE	m,hAChE	TcAChE	mAChE	m,hAChE	TcAChE	mAChE	m,hAChE	TcAChE
Tacrine	4	—	−8	21	—	−6	33	—	−1	−3	—	0	0	—	1
Edrophonium	4	—	2	21	—	−3	33	—	−1	0	—	1	0	—	2
Huperzine A	6	−20	0	21	−13	2	33	−11	2	0	−10	1	0	−13	0
BW284c51	3		7	21		7	35		9	−13		11	−14		15
Decamethonium	3	−10	−10	21	−20	−12	28	−10	−2	−35	3	3	−7	−25	−4
Gallamine	−4	11		14	9		9	2		−25	−5		−14	−1
Fas2	0	−14	−14	21	6	2	35	6	−3	−23	6	−12	−17	−3	−4
TFK+	6	8	1	21	12	−16	35	10	−2	3	16	−1	0	21	−3
Rivastigmine	0		10	−30		11	20		7	−4		10	0		9
Sarin	3	−13	—	11	−9	—	23	−6	—	0	2	—	0	−5	—
VX	−5	−1	—	4	1	—	19	0	—	−11	6	—	0	5	—
DFP	−5	−9	—	−14	−6	—	18	−6	—	−10	−6	—	−3	21	—

Note: Comparison of ligand-associated spectral shifts of acrylodan^12,13 covalently attached at one of five positions in mAChE (76, 81, 84,124, and 287; TcAChE numbering is shown in parentheses) with ligand-associated variability of B factors (Δ B value = (B value: Cα^position_)complex − (B value: Cα^position)_apo) observed from X-ray structures. B value differences observed for mouse AChE (mAChE) and human AChE (hAChE) X-ray structures were similar (for complexes with the same ligand) and are shown in the same column (as m,hAChE), while data for Torpedo californica AChE (TcAChE) structures are shown in a separate column. A list of the structures used in the analysis is given in Table S1.