Table 1. A summary of Tat translocase subunits (A/E, B, C) present in each bacterial class surveyed for this study and the most common arrangement of these genes in tat operons.

Bacterial Class	Total species identified	Total number of genes identified in class			tat operon§ arrangement
		tatA/E	tatB	tatC
Actinobacteria	118	152	78	118	AC ↔ (B/A)
Bacilli	51	57	1	58	AC ↔ (AC)
Clostridia	29	59	7	29	AC
Deinococci	14	35	72	15	AC
α-proteobacteria	129	148	121	131	ABC or C↔A
β-proteobacteria	76	91	74	80	ABC
γ-proteobacteria	166	232	146	170	A2BC(D)
δ-proteobacteria	37	76	23	39	(A/B)C ↔ (A)
ε-proteobacteria	24	21	9	24	BC ↔ A
Chloroflexi	14	361	9	15	A2BC
Planctomycetia/Phycisphaerae	5	9	0	5	C ↔ A2
Chlamydiae	2	2	0	2	AC
Aquificae	9	17	8	9	A2BC
Bacteroidetes	44	61	3	45	AC ↔ (A/B)
Cyanobacteria	15	22	3	17	C ↔ A2
Deferribacteres	4	8	3	4	BC ↔ A2
Fusobacteria	2	2	1	2	C(B)A
Gemmatimonadetes	1	1	0	1	C ↔ A
Chlorobia/Ignavibacteria	11	11	0	11	C ↔ A
Negativicutes	5	5	0	5	AC
Nitrospira	3	6	0	3	C ↔ A2
Acidobacteria/Solibacteres	6	9	3	6	(B)C ↔ A2
Sphingobacteria	8	8	0	8	C ↔ A
Spirochaetes	4	4	0	4	AC
Thermodesulfobacteria	2	2	0	2	AC
Verrucomicrobia	4	8	0	4	C ↔ A2

^§ tat genes are listed as single letters A to C and combinations written together indicate their presence at the same tat operon locus. Bidirectional ↔ arrows indicate that the Tat component genes are not found in the same operon (separate loci). tat genes (A, B or C) found in parentheses indicate an optional occurrence in the tatC locus.