RecA-mediated cleavage activates UmuD for mutagenesis: Mechanistic relationship between transcriptional derepression and posttranslational activation

Journal Article · Tue Mar 01 00:00:00 EST 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.6.1816· OSTI ID:7099047

Nohmi, Takehiko; Battista, J R; Dodson, L A; Walker, G C ^[1]

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1. Massachusetts Institute of Technology, Cambridge (USA)

The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. It has been shown that the UmuD protein shares homology with LexA, the repressor of the SOS genes. In this paper the authors describe a series of genetic experiments that indicate that the purpose of RecA-mediated cleavage of UmuD at its bond between Cys-24 and Gly-25 is to activate UmuD for its role in mutagenesis and that the COOH-terminal fragment of UmuD is necessary and sufficient for the role of UmuD in UV mutagenesis. Other genetic experiments are presented that (i) support the hypothesis that the primary role of Ser-60 in UmuD function is to act as a nucleophile in the RecA-mediated cleavage reaction and (ii) raise the possibility that RecA has a third role in UV mutagenesis besides mediating the cleavage of LexA and UmuD.

• OSTI ID: 7099047
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 85:6; ISSN 0027-8424
• Country of Publication: United States
• Language: English

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CELL CONSTITUENTS
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ELECTROMAGNETIC RADIATION
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LIPOTROPIC FACTORS
MICROORGANISMS
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ORGANIC COMPOUNDS
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