TABLE 3.

relB homologues

Bacterial species	relB genea	Characteristic of the RelB protein
		No. of aa	Molecular mass (kDa)b	pIb
Gram-negative bacteria
E. coli K-12	relBK-12	79	9.1	4.8
E. coli K-12	relBSOSc	86	9.4	5.2
E. coli plasmid P307	relBP307	83	9.2	4.4
E. coli plasmid pB171	relBpB171	83	9.2	4.1
S. enterica serovar Typhi	relBSt1	80	9.0	5.2
P. shigelloides plasmid p11184	relBPs	83	9.2	4.1
H. influenzae	relBHi	98	11.0	4.7
V. cholerae	relBVc	82	8.9	4.4
H. pylori	relBHp1	95	11.4	9.8
H. pylori	relBHp2	95	11.4	10.6
B. fibrisolvens	relBBf	83	9.6	6.6
A. europaeus	relBAe	87	9.5	4.6
M. morganii	relBMm	83	9.2	4.3
T. ferrooxidans	relBTf	74	8.5	4.7
A. aeolicus	relBAq	80	9.3	5.4
Synechosystis	relBSy	86	9.9	4.7
Gram-positive bacteria
B. thuringiensis	relBBt	85	10.1	4.5
M. tuberculosis	relBMt1	93	10.2	4.6
M. tuberculosis	relBMt2	89	9.8	5.1
S. pneumoniae	relBSp1	87	10.0	4.4
S. pneumoniae	relBSp2	80	9.2	4.2
Archaea
M. jannaschii	relBMj1	82	9.6	4.5
A. fulgidus	relBAf1	65	7.8	4.8
A. fulgidus	relBAf2	62	7.4	4.3
A. fulgidus	relBAf3	72	8.5	4.5
A. fulgidus	relBAf4	57	6.7	4.1
P. horikoshii OT3	relBPyr	67	8.0	3.8

^aSubscripts refer to the species in which the relB genes were identified (see the species shown in the leftmost column). 

^bMolecular masses and isoelectric points were calculated by using the Wisconsin GCG package. 

^cThe relBE_SOS system of E. coli K-12 contains a LexA binding site in the promoter region and may belong to the SOS regulon (48).