The architecture of RNA polymerase fidelity

Table 1 The contribution of the trigger loop compared in the E. coli and the T. aquaticus studies

*T. aquaticus*mutation [2]	Substrate/fold defect relative to WT (k_pol[cGTP])	*E. coli*mutation [9]	Substrate/fold defect relative to WT (k_CTP^{25 μM})
Arg1239Ala	GTP/~48	Arg933Ala	CTP/4
His1242Ala	GTP/~100	His936Ala	CTP/6
Arg1239Ala/His1242Ala	GTP/~1400	Arg933Ala/His936	CTP/24
		Ala
Met1238Ala	GTP/~1800	Met932Ala	CTP/70
ΔTL	GTP/~62,500	TL^LTPP*	CTP/12,000
*T. aquaticus* mutation[2]	Substrate/fold selectivity for cGTP	*E. coli* mutation [9]	Substrate/fold selectivity for cATP
WT k_pol^app	2'-cdATP/~1800	WT k_pol^app	ND
WT K_m	2'-cdATP/~20	WT K_m	ND
ΔTL k_pol^app	2'-cdATP/~1.2	ΔTL k_pol^app	2'-cdATP/~27
ΔTL K_m	2'-cdATP/~1.4	ΔTL K_m	2'-cdATP/~4

ND = Not determined. k_pol^app = apparent k_pol. *TL^LTPP is a double-proline substituted mutant in the E. coli TL proposed to compromised folding.

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