Table 2.

Gap distances between NBDs measured based on available structures using different methods

PDB	Nucleotide bound	Construct/Substrate/Inhibitor and Other treatment	Distance (Å)
			COM (NBD1 to NBD2)a	CA (N607-T1252)b
6C0V	ATP	E/Q	20.8	41.3
6FN1	Apo	Crossed linked/Fab/Zusoquidar	34.6	36.3
5KPI	Apo	WT	45.6	41.7
5KPJ	Apo	WT/ methylated	60.5	66.0

a – COM is center of mass. The distance is measured between the COM of NBD1 to that of NBD2

b – CA is Cα atom of an amino acid residue. The distance is measured between Cα of N607 and T1252 or their equivalent residues in human P-gp.