Table 3. Bond Distances (angstroms) in the Nicotinamide Rings of NADH or NAD⁺ in ADH Complexes.

complex	N1–C2	C2–C3	C3–C4	C4–C5	C5–C6	C6–N1
NADH, H2Oa	1.36 ± 0.02	1.35 ± 0.02	1.50 ± 0.02	1.43 ± 0.02	1.44 ± 0.02	1.35 ± 0.02
NADH, MHFb	1.40 ± 0.02	1.36 ± 0.03	1.49 ± 0.05	1.48 ± 0.02	1.33 ± 0.03	1.42 ± 0.06
NADH, BNFc	1.36 ± 0.02	1.35 ± 0.02	1.50 ± 0.03	1.42 ± 0.04	1.36 ± 0.05	1.42 ± 0.02
NADH, variousd	1.40 ± 0.03	1.35 ± 0.02	1.48 ± 0.05	1.47 ± 0.03	1.41 ± 0.04	1.40 ± 0.03
NAD+, FALCe	1.35 ± 0.01	1.36 ± 0.01	1.42 ± 0.01	1.38 ± 0.01	1.37 ± 0.01	1.39 ± 0.01

^aWeighted average of the bond distances and errors for two subunits from refinement with SHELXL-2013 with no restraints on distances or planarity of the nicotinamide ring (PDB entry 4XD2).

^bTwo structures (1.25 and 1.57 Å resolution) with N-1-methylhexylformamide, with an average of eight subunits and the standard deviation from refinement with REFMAC (PDB entries 1P1R and 5VN1).

^cAverage of four subunits of the structure with NADH and N-benzylformamide (PDB entry 5VL0) after restrained refinement with REFMAC and calculation with SHELXL-2103.

^dFour structures (1.0–1.2 Å resolution) with an average of eight subunits and the standard deviation in complexes with NADH and various ligands (PDB entries 1HET, 1HEU, 2JHG, and 1JHF) refined with relaxed restraints on the nicotinamide ring.^22,23

^eWeighted average for four subunits with SHELXL-2013 refinement with no restraints on the nicotinamide ring in complexes with NAD⁺ and fluoro alcohols (PDB entries 4DWV and 4DXH).⁶²