3.4.21.B30 malfunction effects of recA and umuD mutations on UmuDAb cleavage in DNA damage response of Escherichia coli 731823 3.4.21.B30 malfunction for cleavage to occur, UmuD S60A and UmuD G25D mutant dimers 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 metabolism competition between enzyme UmuD and ssDNA for DNA polymerase III alpha binding is a distinct mechanism for polymerase exchange 732588 3.4.21.B30 additional information Acinetobacter UmuDAb possesses both the conserved serine-lysine catalytic dyad required by UmuD, LexA, and some bacteriophage repressors for self-cleavage as well as the (Ala/Cys)-Gly cleavage site 731823 3.4.21.B30 additional information intermolecular mechanism of UmuD self-cleavage of enzyme dimers, overview 731823 3.4.21.B30 additional information UmuD proteins are shown to adopt multiple conformations in solution, homology models of UmuD and the structure of UmuD', overview. The heterodimer is the predominant UmuD protein conformer -, 731345 3.4.21.B30 physiological function in the DNA damage response, UmuD forms part of the error-prone (UmuD'2)C polymerase V, and is activated for this function by self-cleavage after DNA damage. The umuD homologue umuDAb regulates transcription of DNA-damage induced genes. DNA damage from mitomycin C or UV exposure causes UmuDAb cleavage in both Escherichia coli wild-type and DELTAumuD cells on a timescale resembling UmuD, but does not require UmuD. UmuD and UmuDAb require RecA for cleavage 731823 3.4.21.B30 physiological function the active form of DNA polymerase V is UmuD'2C-RecA-ATP. RecA* transfers a single RecA-ATP stoichiometrically from its DNA 3'-end to free pol V (UmuD'2C) to form an active mutasome with the composition UmuD'2C-RecA-ATP 705887 3.4.21.B30 physiological function the plasmid (pUM505)-encoded UmuD homologue regulates expression of Pseudomonas aeruginosa SOS genes. The UmuDpR protein is a repressor of Pseudomonas aeruginosa SOS genes controlled by LexA 754656 3.4.21.B30 physiological function the protein UmuD is extensively involved in modulating cellular responses to DNA damage and may play a role in DNA polymerase exchange for damage tolerance. The polymerase manager protein UmuD directly regulates Escherichia coli DNA polymerase III alpha binding to ssDNA 732588 3.4.21.B30 physiological function the umuD gene products are upregulated after DNA damage and play roles in both nonmutagenic and mutagenic aspects of the SOS response -, 752775 3.4.21.B30 physiological function The umuD gene products perform distinct functions in preventing and facilitating mutagenesis. The full-length dimeric UmuD2 is the initial product that is expressed shortly after the induction of the SOS response and inhibits bacterial mutagenesis, allowing for error-free repair to occur. The slow auto-cleavage of UmuD2 to UmuD'2 promotes mutagenesis to ensure cell survival. The intracellular levels of UmuD2 and UmuD?2 are further regulated by degradation in vivo, returning the cell to a nonmutagenic state. Dynamic regulatory roles of the umuD gene, overview. UmuD lifecycle involves dimer exchange and cleavage in the regulation of the DNA damage respons -, 731345 3.4.21.B30 physiological function UmuD is a dynamic protein that regulates mutagenesis. The UmuD gene products, regulated by the SOS response, exist in two principal forms: UmuD2, which prevents mutagenesis, and UmuD’2, which facilitates UV-induced mutagenesis. UmuD slows the resumption of DNA replication after UV irradiation. UmuD interacts with DinB and inhibits its mutagenic -1 frameshift activity. UmuD2 interacts with the RecA/ssDNA filament, which stimulates the ability of UmuD to cleave itself 718023 3.4.21.B30 physiological function UmuD is implicated in a primitive DNA damage checkpoint and prevents DNA polymerase IV-dependent -1 frameshift mutagenesis, while the cleaved form UmuD' facilitates UmuC-dependent mutagenesis via formation of DNA polymerase V (UmuD'2C). Thus, the cleavage of UmuD is a crucial switch that regulates replication and mutagenesis via numerous protein-protein interactions. 709543 3.4.21.B30 physiological function UmuD regulates the cellular response to DNA damage 717851 3.4.21.B30 physiological function UmuD2 is the initial umuD gene product that appears after induction of the SOS response. It is involved in regulating mutagenesis as part of the tightly controlled SOS response 718102 3.4.21.B30 physiological function UmuD2, when bound to DinB, displaces the equilibrium in favor of the non-slipped conformation, thereby preventing frameshifting and potentially enhancing DinB activity on non-slipped substrates. DinB template slippage is inhibited by UmuD2 709122 3.4.21.B30 physiological function when bound to UmuC, the enzyme functions as a checkpoint in delaying cell division, allowing time for error-free repair mechanisms to act, error-prone polymerase accessory UmuD. UmuD is not required for UmuDAb expression from its native promoter, nor its disappearance after DNA damage through intermolecular interactions with Escherichia coli UmuD 731823