Table S1.

Point mutations that do not perturb the up/down NTD equilibrium in ND1Lp97-ADP

Mutation at	Mutated to	CSP*	RD†	Other observations	Mutation at	Mutation to	CSP*	RD†
L17	I			Located in N-terminal helix that is formed in the ATP state only	V320	I
I27	V	x		Associated with disease (38) but also found in healthy control patients (12)	I324	V
I32	V		x		V325	I
K63	A			Affects salt bridge formation in ATP state	M332	L
	E
V71	I				L335	M
V123	I	x			V341	I
I126	L				M344	I		x
M158	L	x		Location of disease mutation M158V	I353	V		x
I189	V	x	x	Located at the beginning of linker helix	V367	I
E194	P			Located in the middle of linker helix; affects helix formation in ATP state	I369	V
V201	I		x	Located at the end of linker helix	L378	M
I206	V			Location of disease mutation I206F	I380	V
L213	M	x	x		I383	V
M219	L		x		M388	L	x	x
I233	L				V407	T
V235	I				L420	M
L253	I				I423	V
V258	I				M427	L		x
L268	M				L429	M
I269	V				L432	I
I274	V	x	x		M442	L		x
M275	L				L445	M	x
L278	M				V447	I
I300	V				L464	M
E305	Q			Walker B position	V468	I
I309	V				V471	L

^*For each residue, it is noted whether the δ₁ (Ile), γ₁ (Val), or δ₁ (Leu) methyl peak position is sensitive to the NTD up/down equilibrium [x, combined ¹³C and ¹H chemical shift differences between ND1Lp97-ADP and R95G mutant exceeds 0.25 ppm, $\sqrt{(0.25{\mathrm{\Delta }{\varpi }_C)}^2+{\left(\mathrm{\Delta }{\varpi }_H\right)}^2}$> 0.25 ppm, where Δϖ is in ppm].

^†The x indicates that ΔR_2,eff > 1.5 s⁻¹, where ΔR_2,eff = R_2,eff (ν_CPMG = 50 Hz) – R_2,eff (ν_CPMG = 2,000 Hz) in relaxation dispersion profiles recorded on R95G ND1Lp97-ADP.