Table 1.

Qmo complex sequences used in phylogenetic tree construction, their annotation and properties.

	Qmo complex subunit ortholog annotations
	QmoA				QmoB				QmoC
	Heterodisulfide reductase subunit A				Heterodisulfide reductase, subunit A/hydrogenase, delta subunit, putative				Heterodisulfide reductase, transmembrane subunit, putative
	4Fe–4S ferredoxin, iron–sulfur binding domain protein				Heterodisulfide reductase, subunit A and related polyferredoxins/Coenzyme F420-reducing hydrogenase, delta subunit				Heterodisulfide reductase, subunit E, putative
Genome	Locus tag	Length	SigP	TM	Locus tag	Length	SigP	TM	Locus tag	Length	SigP	TM
CHLOROBIA
Chlorobaculum tepidum TLS	CT0866	413	Yes	No	CT0867	750	No	No	CT0868	391	No	Yes
Chlorobium phaeobacteroides BS1	Cphamn1_1836	413	Yes	No	Cphamn1_1835	750	No	No	Cphamn1_1834	391	No	Yes
Chlorobium chlorochromatii CaD3	Cag_1584	412	Yes	No	Cag_1583	750	No	No	Cag_1582	392	No	Yes
Pelodictyon phaeoclathratiforme BU-1	Ppha_0037	413	Yes	No	Ppha_0036	750	No	No	Ppha_0035	393	No	Yes
DELTAPROTEOBACTERIA
Desulfovibrio vulgaris Hildenborough	DVU0848	412	Yes	No	DVU0849	758	No	No	DVU0850	384	No	Yes
D. vulgaris DP4	Dvul_2135	412	Yes	No	Dvul_2134	758	No	No	Dvul_2133	384	No	Yes
D. vulgaris Miyazaki F	DvMF_2894	412	Yes	No	DvMF_2895	754	No	No	DvMF_2896	384	No	No
Desulfovibrio desulfuricans G20	Dde_1111	412	Yes	No	Dde_1112	756	No	No	Dde_1113	384	No	Yes
D. desulfuricans ATCC 27774	Ddes_2127	411	Yes	No	Ddes_2126	756	No	No	Ddes_2125	393	No	Yes
Desulfovibrio piger ATCC 29098	DESPIG_02771	411	Yes	No	DESPIG_02770	753	No	No	DESPIG_02769	394	No	Yes
Desulfovibrio magneticus RS-1	DMR_05410	413	Yes	No	DMR_05420	763	No	No	DMR_05430	399	No	Yes
Desulfomicrobium baculatum DSM 4028	Dbac_3199	413	Yes	No	Dbac_3200	763	No	No	Dbac_3201	408	No	Yes
Desulfohalobium retbaense DSM 5692	Dret_1965	411	Yes	No	Dret_1964	766	No	No	Dret_1963	407	No	Yes
Desulfurivibrio alkaliphilus AHT2	DaAHT2_1470	419	Yes	No	DaAHT2_1469	752	No	No	DaAHT2_1468	397	No	Yes
Desulfotalea psychrophila LSv54	DP1106	445	No	No	DP1107	753	No	No	DP1108	404	No	Yes
Desulfatibacillum alkenivorans AK-01	Dalk_1568	424	Yes	No	Dalk_1567	774	No	No	Dalk_1566	413	No	Yes
Desulfococcus oleovorans Hxd3	Dole_0999	423	Yes	No	Dole_1000	778	No	No	Dole_1001	398	No	Yes
Desulfobacterium autotrophicum HRM2	HRM2_04500	424	Yes	No	HRM2_04490	778	No	No	HRM2_04480	391	No	Yes
Syntrophobacter fumaroxidans MPOB	Sfum_1287	420	Yes	No	Sfum_1286	738	No	No	Sfum_1285	385	No	Yes
BETAPROTEOBACTERIA
Thiobacillus denitrificans ATCC 25259	Tbd_1648	427	No	No	Tbd_1647	752	No	No	Tbd_1646	210	No	No
NITROSPIRA
Thermodesulfovibrio yellowstonii	THEYE_A1831	415	No	No	THEYE_A1830	744	No	No	THEYE_A1829	382	No	No
ARCHAEOGLOBUS
Archaeoglobus fulgidus DSM 4304	AF0663	404	No	No	AF0662	747	No	No	AF0661	379	No	Yes
Archaeoglobus profundus DSM 5631	Arcpr_1260	420	Yes	No	Arcpr_1259	740	No	No	Arcpr_1258	421	No	Yes

Length = amino acid residues in gene product, SigP = signal peptide prediction, TM = transmembrane helix prediction.