Table I.

Summary of mutations (in bold). MJ25^R (microcin J25 resistance); STL^R (streptolydigin resistance).

Sc RNAP II	Tt RNAP	Ec RNAP	Activity	References
Rpb1 G820	β’ A1077	β’ A779G/T/P	MJ25R	[70]
Rpb1 R821	β’ R1078	β’ R780H/C	Rapid elongation rate, altered termination efficiency/ MJ25R	[71]/[70]
Rpb1 G823	β’ G1080	β’ G782A	MJ25R	[70]
Rpb1 L1081I/M/T/R/V	β’ M1238	β’ M932A	Slow elongation	[58, 59, 76]
Rpb1 F1084Q/A/S/H/I	β’ F1241	β’ F935A	Slow elongation	[58, 59, 76]
Rpb1 H1085Y/F/A	β’ H1242	β’ H936A/Y	Slow elongation, Sc H1085F/A lethal	[58, 59, 76]
Rpb2 R504A	β R420	β R540	Little effect	[27]
Rpb2 D505A	β E421	β E541	Little effect	[27]
Rpb2 K507	β A423	β A543P/V/T	STLR	[77]
Rpb2 L508	β G424	β G544D/R	MJ25R, STLR	[70, 77]
Rpb2 A509	β F425	β F545S/C/I/L	MJ25R, slow elongation, STLR	[27, 67, 70]
Rpb2 K510A	β D426	β E546V	Little effect/STLR	[27, 67]
Rpb2 R512A/C	β R428	β R548Q	Slow elongation rate/ MJ25R	[27], this paper/[70]
Rpb2 Q513A	β D429	β D549H	Little effect/ MJ25R	[27]/[70]
Rpb2 L514	β V430	β V550E	Mimic ppGpp effect	[78]
Rpb2 H515	β H431	β H551P/Y	Mimic ppGpp effect, reduced termination	[72, 78]
Rpb2 P524	β P440	β P560L/S	Slightly reduced elongation rate, reduced termination	[72–74]
Rpb2 T527	β T443	β T563P	Mimic ppGpp effect	[75, 78]
Rpb2 P528	β P444	β P564S	Suppressor G566D ts	[74]
Rpb2 E529A/Q/D	β E445	β D565	Sc E529A/D rapid in elongation, E529Q slow in elongation	[27]
Rpb2 G530	β G446	β G566D/K	Slow elongation rate, attenuation and termination defects	[74]
Rpb2 Q531	β A447	β P567S	Reduced termination	[72]
Rpb2 G534	β G450	β G570C	STLR	[67]
Rpb2 L535	β L451	β L571Q/R/P	Mimic ppGpp effect	[75, 78]
Rpb2 V536	β I452	β I572S	Mimic ppGpp effect	[78]
Rpb2 R766Q/A	β R557	β R678C	Lethal in Sc, Minor defect in Ec	This paper, [54]