Table 4.

Amino acids constituting an odorant and copper-binding site in OR2M3

TMH segmenta	AA position within TMH segmenta	Mutagenesis-validated 3-Mercapto-2-methyl-pentan-1-ol binding site positions	3-Mercapto-2-methyl-pentan-1-ol	Copper	3-Mercapto-2-methyl-pentan-1-ol and copper	Validated positions in other ORs
TMH 3	8	b,cThr1053.33	H-bond	Indirect	H-bond	His1053.33: [30], His1083.33: [31], Ile1053.33: [64], Met1053.33: [9], His1083.33: [106], Cys1063.33: [50, 98]
TMH 3	21	Met1183.46	No interaction	Direct	Direct	Met1153.46: [31]
TMH 5	5	cCys2025.41	H-bond	Direct	H-bond via copper	Asn2025.41: [30], Thr2025.41: [9], Asn2025.41: [97], Thr2055.41: [95]
TMH 5	6	bCys2035.42	No interaction	Direct	H-bond via copper	Thr2035.42: [97], Val2065.42: [107], Phe2075.42: [95]
TMH 6	1	cCys2416.33	Indirect	Direct	Direct	Cys2386.33: [31]
TMH 6	4	His2446.36	No interaction	Direct	Direct	His2416.36: [31]

^aHORDE [81]

^bProposed amino acid positions constituting an odorant-binding site according to Man et al. [88]

^c3-Mercapto-2-methylpentan-1-ol-binding site in OR2M3