3.4.21.B30	A30T	substantial extent of proteolytic cleavage	653604	
3.4.21.B30	A31C	partial reduction in UV mutability	651629	
3.4.21.B30	A31C	UmuD’ mutant	718102	
3.4.21.B30	A7C/C24A/S60A	variant with maximal cross-linking	-, 755139	
3.4.21.B30	A83X	the site-directed mutation of UmuDAb at Ala83 abolishes cleavage activity	731823	
3.4.21.B30	A89C	reduced ability to for a heterodimer with UmuD'	651622	
3.4.21.B30	C24A	ability to participate in UV mutagenesis and RecA-mediated cleavage are similar to that of the wild-type enzyme	651622	
3.4.21.B30	C24A	site-directed mutagenesis, that removes the cleavage site Cys residue of UmuD, the mutation does not substantially affect UmuD function, cleavage site variant	-, 731345	
3.4.21.B30	C24Y	poor extent of proteolytic cleavage	653604	
3.4.21.B30	C25D	site-directed mutagenesis, that removes the cleavage site Cys residue of UmuD, the mutation does not substantially affect UmuD function, cleavage site variant. For cleavage to occur, UmuD UmuD G25D dimer must first exchange in the presence of RecA:ssDNA, and any cleavage detected results from cleavage in trans. Cleavage is less efficient in this context, indicating that the decreased rate of cleavage in the trans dimers results from the time required for dimer exchange to first take place before cleavage can occur	-, 731345	
3.4.21.B30	D126C	reduced ability to form a homodimer and a heterodimer with UmuD'	651622	
3.4.21.B30	D20Y	slight increase in activation rate by cleavage	652782	
3.4.21.B30	D32C	deficiencies in RecA-mediated cleavage as well as in UV mutagenesis, less than 30% of the wild-type activity	651629	
3.4.21.B30	D3A	the UmuD variant is non-cleavable but is a partial biological mimic of the cleaved form UmuD	709543	
3.4.21.B30	D91A	the mutant is soluble and purifies as the wild type UmuD	-, 681885	
3.4.21.B30	D91K	site-directed mutagenesis, the mutation abolishes the interaction between the enzyme and the DNA polymerase III alpha subunit	732588	
3.4.21.B30	E11V/I12V/V13K	supports ClpXP degradation of UmuD'	653588	
3.4.21.B30	E35C	deficiencies in RecA-mediated cleavage as well as in UV mutagenesis, less than 30% of the wild-type activity	651629	
3.4.21.B30	F15A	slight decrease of induced mutagenesis compared to wild-type	669529	
3.4.21.B30	F15L	no change in activation rate by cleavage	652782	
3.4.21.B30	F18A	decrease of induced mutagenesis to 20% of wild-type level, no cleavage of UmuD	669529	
3.4.21.B30	F26A/P27A/S28A/P29A	can form heterodimers and is recognized by ClpXP protease	650976	
3.4.21.B30	G129D	poor extent of proteolytic cleavage	653604	
3.4.21.B30	G25D	medium extent of proteolytic cleavage	653604	
3.4.21.B30	G25S	poor extent of proteolytic cleavage	653604	
3.4.21.B30	G65R	defective for RecA-mediated UmuD cleavage	653236	
3.4.21.B30	G65R	medium extent of proteolytic cleavage	653604	
3.4.21.B30	G92C	site-directed mutagenesis of of UmuD'	-, 731345	
3.4.21.B30	G92D	substantial extent of proteolytic cleavage	653604	
3.4.21.B30	G92K	site-directed mutagenesis, the mutation abolishes the interaction between the enzyme and the DNA polymerase III alpha subunit	732588	
3.4.21.B30	G92N	defective for RecA-mediated UmuD cleavage	653236	
3.4.21.B30	I38C	poor reaction with iodoacetate	651629	
3.4.21.B30	I4F	slight increase in activation rate by cleavage	652782	
3.4.21.B30	K156X	the site-directed mutation of UmuDAb at Lys156 abolishes cleavage activity	731823	
3.4.21.B30	K97A	mutant is able to undergo intermolecular cleavage, but not intramolecular self-cleavage	651420	
3.4.21.B30	L101G/R102G	mutant enzyme is defective in RecA-ssDNA-facilitated self-cleavage in vivo, can undergo RecA-ssDNA-facilitated cleavage in vitro, can interact directly with the RecA-ssDNA nucleoprotein filament in vitro, and is active in SOS mutagenesis in vivo	651685	
3.4.21.B30	L107F	substantial extent of proteolytic cleavage	653604	
3.4.21.B30	L17F	no change in activation rate by cleavage	652782	
3.4.21.B30	L40C	less than 30% of the wild-type activity, although defective in UV mutagenesis and in vitro RecA-mediated cleavage, mutant is able to be cleaved efficiently by RecA in vivo	651629	
3.4.21.B30	L44C	4-azidoiodoacetanilide-modified mutant, almost no cross-linking with RecA	651628	
3.4.21.B30	L44C	reduced ability to form a homodimer	651622	
3.4.21.B30	L9A/R10A/E11A/I12A	heterodimer with UmuD' displays a significant increase in stability	650976	
3.4.21.B30	additional information	characterization of two truncation variants of the Escherichia coli polymerase manager protein UmuD, UmuDELTA 8 (UmuD DELTA1-7) and UmuDELTA 18 (UmuS DELTA1-17). The loss of the N-terminal seven amino acids of UmuD results in changes in conformation of the N-terminal arms. UmuD 8 is cleaved as efficiently as full-length UmuD in vitro and in vivo, but expression of a plasmid-borne non-cleavable variant of UmuD 8 causes hypersensitivity to UV irradiation. UmuD 18 does not cleave to form UmuD', but confers resistance to UV radiation. Removal of the N-terminal seven residues of UmuD maintains its interactions with the alpha polymerase subunit of DNA polymerase III as well as its ability to disrupt interactions between alpha and the beta processivity clamp, whereas deletion of the N-terminal 17 residues results in decreases in binding to alpha and in the ability to disrupt the alpha-beta interaction. UmuD 8 mimics full-length UmuD in many respects, whereas UmuD 18 lacks a number of functions characteristic of UmuD. Deletion of the first eight residues does not change the cross-linking efficiency compared to UmuD. Deletion of the first 18 residues causes increased cross-linking efficiency, which is likely due to reduced interaction between the arms and the globular domain in the case of UmuD 18	-, 755139	
3.4.21.B30	additional information	generation of DELTAumuD mutant cells	731823	
3.4.21.B30	additional information	generation of isogenic mutant UmuDC homologues A1S_0636-A1S_0637, A1S_1174-A1S_1173, and A1S_1389, the mutants are less able to acquire resistance to rifampin and streptomycin through the activities of their error-prone DNA polymerase, but neither the growth rate nor the UV-related survival of any of the three mutants is significantly different from that of the wild-type parental strain	-, 731145	
3.4.21.B30	N41D	site-directed mutagenesis, the monomeric UmuD N41D variant can only cleave in the cis conformation	-, 731345	
3.4.21.B30	N41D	the mutant generates stable, active UmuD and UmuD’ monomers that functionally mimic the dimeric wild type proteins. The mutant is proficient for cleavage and interacts physically with DNA polymerase IV (DinB) and the beta-clamp, facilitates UV-induced mutagenesis and promotes overall cell viability	717851	
3.4.21.B30	P27S	defective for RecA-mediated UmuD cleavage	653236	
3.4.21.B30	P27S	substantial extent of proteolytic cleavage	653604	
3.4.21.B30	P48G	expression of UmuD2 P48G is substantially lower than that of wild type UmuD2	717851	
3.4.21.B30	Q23P	mutant phenotype is reminiscent of the wild-type	652782	
3.4.21.B30	Q23P/S60A	UmuD is non-cleavable via an intramolecular cleavage pathway, but it remains cleavable via the intermolecular pathway	652782	
3.4.21.B30	R37A	when mutation is present in the UmuD' subunit of a UmuD/D' heterodimer it causes this subunit to be degraded substantially more slowly than its wild-type counterpart, when the mutation is present in the UmuD subunit of the heterodimer degradation of the UmuD' subunit occurs as efficiently as with the wild-type enzyme	653588	
3.4.21.B30	R37C	poor reaction with iodoacetate	651629	
3.4.21.B30	S112C	4-azidoiodoacetanilide-modified mutant, cross-links moderately efficiently with RecA	651628	
3.4.21.B30	S119X	the site-directed mutation of UmuDAb at Ser119 abolishes cleavage activity	731823	
3.4.21.B30	S19C	4-azidoiodoacetanilide-modified mutant, almost no cross-linking with RecA	651628	
3.4.21.B30	S57C	4-azidoiodoacetanilide-modified mutant, cross-links moderately efficiently with RecA	651628	
3.4.21.B30	S57C	reduced activity in UV mutagenesis	651622	
3.4.21.B30	S60A	active-site UmuD mutant	718102	
3.4.21.B30	S60A	non-cleavage variant	-, 755139	
3.4.21.B30	S60A	noncleavable UmuD variant	-, 681885	
3.4.21.B30	S60A	site-directed mutagenesis, a non-cleavable mutant of UmuD and UmuD', inactive active site mutant. For cleavage to occur, UmuD S60A dimer must first exchange in the presence of RecA:ssDNA, and any cleavage detected results from cleavage in trans. Cleavage is less efficient in this context, indicating that the decreased rate of cleavage in the trans dimers results from the time required for dimer exchange to first take place before cleavage can occur	-, 731345	
3.4.21.B30	S60C	4-azidoiodoacetanilide-modified mutant, no cross-linking with RecA	651628	
3.4.21.B30	S60C	similar in iodoacetate reactivity but cross-links less efficiently by I2 oxidation than the wild-type enzyme, reduced activity in UV mutagenesis	651622	
3.4.21.B30	S67C	4-azidoiodoacetanilide-modified mutant, cross-links moderately efficiently with RecA	651628	
3.4.21.B30	S67C	only 9% as active as the wild-type enzyme in UV mutagenesis	651622	
3.4.21.B30	S81C	4-azidoiodoacetanilide-modified mutant, cross-links most efficiently with RecA	651628	
3.4.21.B30	T14A	slight decrease of induced mutagenesis compared to wild-type	669529	
3.4.21.B30	T14A/F15A/F18A	decrease of induced mutagenesis to 20% of wild-type level, no cleavage of UmuD	669529	
3.4.21.B30	T14A/L17A/F18A	the mutant is a non-cleavable variant of UmuD	718102	
3.4.21.B30	T14P	no change in activation rate by cleavage	652782	
3.4.21.B30	T95M	substantial extent of proteolytic cleavage	653604	
3.4.21.B30	V135S/K136A/R139A	expression of UmuD2 V135S/K136A/R139A is substantially lower than that of wild type UmuD2	717851	
3.4.21.B30	V34C	4-azidoiodoacetanilide-modified mutant, cross-links most efficiently with RecA	651628	
3.4.21.B30	V34C	defective for RecA-mediated cleavage	651630	
3.4.21.B30	V34C	reduced activity in UV mutagenesis	651622	
3.4.21.B30	Y33C	less than 30% of the wild-type activity, although defective in UV mutagenesis and in vitro RecA-mediated cleavage, mutant is able to be cleaved efficiently by RecA in vivo	651629