Table 1 Summary of mutations. 6-AU ^s indicates sensitivity to 6-azauracil

Switch residue

β R557

β R678C

Rpb2 R766Q/A

Lethal

(Ec minor defects)

[13, 38]

Switch residue

β N683

β N811

Rpb2 N834A

6-AU^s

Very slow, moderate fidelity defect

this paper

Mg²⁺ binding

β E685

β E813

Rpb2 E836A

6-AU^s

Slow, severe fidelity defect (Ec slow elongation)

this paper [40, 42, 48, 49]

Mg²⁺ binding

β D686

β D814

Rpb2 D837A

Lethal

(Ec slow elongation)

this paper [42, 48]

Switch residue

β N872

β N1099

Rpb2 1013A

Slow

this paper

γ-phosphate

β S878

β S1105

Rpb2 S1019F

6-AU^s

Slow, severe fidelity defect

this paper

γ-phosphate

β R879

β R1106

Rpb2 R1020K/Q

Lethal

[43]

Switch residue

β’ D784

β’ D505

Rpb1 D526A

Lethal

this paper

H3/H4 hinges, bridge helix

Rpb1 G819A, G820A, G823A

Lethal

this paper

H3 hinge, bridge helix

β’ G1076

β’ G778

Rpb1 G819A

Slow, minor fidelity defect

this paper, [14, 35]

H3 hinge, bridge helix

β’ A1077

β’ A779

Rpb1 G820A

Slow, moderate fidelity defect

this paper, [14, 35]

H3/H4 hinges, bridge helix

β’ R1078

β’ R780C

Rpb1 R821Q/A

R821Q slow, R821A lethal (Ec termination defects)

this paper, [50][14, 35]

H3/H4 hinges, bridge helix

β’ K1079

β’ K781A

Rpb1 E822

(Ec very slow elongation)

[35]

H4 hinge, bridge helix

β’ G1080

β’ G782

Rpb1 G823A

Little effect, moderate fidelity defect

this paper, [14, 35]

H1 hinge, trigger loop

Rpb1 G1073A, P1075A

Lethal

this paper

H1 hinge, trigger loop

β’ G1230

β’ G924

Rpb1 G1073A

Slow, strong fidelity defect

this paper, [2]

H1 hinge, trigger loop

β’ E1231

β’ E925

Rpb1 E1074A

Fast

this paper, [2]

H1 hinge, trigger loop

β’ P1232

β’ P926

Rpb1 P1075A

Lethal

this paper, [2]

H1 hinge, trigger loop

β’ T1234

β’ T928

Rpb1 T1077A

Lethal

this paper, [2]

H1 hinge, trigger loop

β’ Q1235A

β’ Q929

Rpb1 Q1078A

Lethal

(Slow, error-prone in Tt)

this paper, [2, 29, 33]

H2 hinge, trigger loop

Rpb1 G1097A, P1099A

Rapid in elongation, moderate fidelity defect

this paper, [2]