3.4.21.B30 proteolytic modification full-length UmuD is expressed as a homodimer of 139-amino-acid subunits, which eventually cleaves its N-terminal 24 amino acids to form UmuD'. The cleavage product UmuD' and UmuC form the Y-family polymerase DNA Pol V (UmuD'2C) capable of performing translesion synthesis -, 752775 3.4.21.B30 proteolytic modification inactive form UmuD is cleaved into active form UmuD' 651628 3.4.21.B30 proteolytic modification inactive UmuD is posttranslationally activated by a RecA-mediated cleavage at its Gys24-Gly25 bond that yields UmuD', UmuD monomer is a better substrate for the cleavage reaction than the dimer 651630 3.4.21.B30 proteolytic modification inactive UmuD is posttranslationally activated by a RecA-mediated cleavage that yields UmuD' 650976, 653236 3.4.21.B30 proteolytic modification inactive UmuD is posttranslationally activated by a RecA-mediated cleavage that yields UmuD', P67D and P67R mutations of RecA result in reduced UmuD cleavage 652778 3.4.21.B30 proteolytic modification processing of UmuD to the shorter, but mutagenically active UmuD' by activated RecA 653602 3.4.21.B30 proteolytic modification processing of UmuD to the shorter, but mutagenically active UmuD' by ClpXP protease, UmuD' must form a heterodimer with its unabbreviated precursor for efficient degradation, UmuD2 homodimers are degraded with an efficiency similar to the UmuD' subunit of the UmuD/UmuD' heterodimer 653588 3.4.21.B30 proteolytic modification RecA-facilitated cleavage of UmuD to UmuD' can be inhibited by overexpression of polymerase III subunits that interact with UmuD 653620 3.4.21.B30 proteolytic modification RecA-facilitated cleavage of UmuD yields a carboxy-terminal fragment UmuD' that is active for mutagenesis, no other SOS gene products other than activated RecA are required for UmuD processing, high levels of activated RecA are required for cleavage in vivo 653235 3.4.21.B30 proteolytic modification RecA-mediated posttranslational processing of UmuD to the shorter, but mutagenically active UmuD' 652782