. 2021 Nov 29;145(1):45–63. doi: 10.1093/brain/awab426

Table 1.

Complex I subunits

Number	LS-linked^a	Name^b	Module^c	Alternative names	Remarks
1	+	NDUFV1	N	51-kDa, Nqo1, NuoF	Contains FMN and N3
2	+	NDUFV2	N	24-kDa, Nqo2, NuoE	Contains N1a
3	−	NDUFV3^d	N	10-kDa
4	+	NDUFS1	N	75-kDa, Nqo3, NuoG	Contains N1b, N4, N5
5	+	NDUFS6	N	13-kDa	Contains Zn²⁺ binding site
6	+	NDUFA12	N	B17.2
7	+	NDUFS4	N/Q?	AQDQ, 18-kDa
8	+	NDUFA2	N/Q?	B8	Contains thioredoxin fold
9	+	NDUFS2	Q	49-kDa, Nqo4, NuoCD
10	+	NDUFS3	Q	30-kDa, Nqo5, NuoCD
11	+	NDUFS7	Q	PSST, Nqo6, NuoB	Contains N₂
12	+	NDUFS8	Q	TYKY, Nqo9, NuoI	Contains N6a and N6b
13	−	NDUFA5	Q	B13
14	−	NDUFA6	Q	B14	LYR
15	−	NDUFA7	Q	B14.5a
16	+	NDUFA9	Q	39-kDa	Short-chain dehydrogenase/reductase fold with bound NAD(P)H
17	−	NDUFAB1	Q & Pd	SDAP-a, SDAP-b	Acyl carrier protein; 2 copies present; contains phosphopantetheine cofactor
18	−	NDUFS5	Pp	15-kDa	Quadruple CX₉C domain; double CHCH domain
19	+	NDUFA1	Pp	MWFE	STMD
20	−	NDUFA3	Pp	B9	STMD
21	−	NDUFA8	Pp	PGIV	Quadruple CX₉C domain; double CHCH domain
22	+	NDUFA10	Pp	42-kDa	Nucleoside kinase family
23	+	NDUFA11	Pp	B14.7
24	+	NDUFA13	Pp	B16.6	Identical to GRIM19, STMD
25	−	NDUFC1	Pp	KFYI	STMD
26	+	NDUFC2	Pp	B14.5b
27	+/−	*MT-ND1*	Pp	Nqo8, NuoH, ND1	8 TMHs
28	+	*MT-ND2*	Pp	Nqo14, NuoN, ND2	11 TMHs
29	+	*MT-ND3*	Pp	Nqo7, NuoA, ND3	3 TMHs
30	−	*MT-ND4L*	Pp	Nqo11, NuoK, ND4L	3 TMHs
31	+	*MT-ND6*	Pp	Nqo10, NuoJ, ND6	5 TMHs
32	−	NDUFB1	Pd	MNLL	STMD
33	−	NDUFB2	Pd	AGGG	STMD
34	−	NDUFB3	Pd	B12	STMD
35	−	NDUFB4	Pd	B15	STMD
36	−	NDUFB5	Pd	SGDH	STMD
37	−	NDUFB6	Pd	B17	STMD
38	−	NDUFB7	Pd	B18	Double CX₉C domain; double CHCH domain
39	+	NDUFB8	Pd	ASHI	STMD
40	−	NDUFB9	Pd	B22	LYR
41	−	NDUFB10	Pd	PDSW
42	−	NDUFB11	Pd	ESSS	STMD
43	+	*MT-ND4*	Pd	Nqo7, NuoM, ND4	14 TMHs
44	+	*MT-ND5*	Pd	Nqo12, NuoL, ND5	16 TMHs

CHCH = coiled-coil-helix-coiled-coil-helix; FMN = flavin mononucleotide; LYR = member of mitochondrial LYR (LYRM) protein family; N = iron-sulphur cluster; O = for ovine CI; STMD = small single transmembrane domain; TMH = transmembrane helices. Adapted from Guerrero-Castillo et al.,¹⁹ Fiedorczuk and Sazanov,²⁰ Adjobo-Hermans et al.,⁶⁴ and Zhu et al.¹⁹²

^{^a}

Linked to Leigh syndrome (LS; OMIM #256000; compiled using a literature search and information from: www.omim.org; +/− marks a potential link).

^{^b}

Human protein name according to HGNC (www.genenames.org). Core subunits are highlighted in bold. Subunits encoded by the mtDNA are in italics.

^{^c}

Functional modules: N (NADH binding and oxidation), Q (electron transfer to ubiquinone), P module (consisting of Pp and Pd submodules, proton pumping).

^{^d}

Represents the NDUFV3-10 subunit (10 kDa).