Genetic separation of Escherichia coli recA functions for SOS mutagenesis and repressor cleavage.
AUTOR(ES)
Ennis, D G
RESUMO
Evidence is presented that recA functions which promote the SOS functions of mutagenesis, LexA protein proteolysis, and lambda cI repressor proteolysis are each genetically separable from the others. This separation was observed in recombination-proficient recA mutants and rec+ (F' recA56) heterodiploids. recA430, recA433, and recA435 mutants and recA+ (F' recA56) heterodiploids were inducible for only one or two of the three functions and defective for mutagenesis. recA80 and recA432 mutants were constitutively activated for two of the three functions in that these mutants did not have to be induced to express the functions. We propose that binding of RecA protein to damaged DNA and subsequent interaction with small inducer molecules gives rise to conformational changes in RecA protein. These changes promote surface-surface interactions with other target proteins, such as cI and LexA proteins. By this model, the recA mutants are likely to have incorrect amino acids substituted as sites in the RecA protein structure which affect surface regions required for protein-protein interactions. The constitutively activated mutants could likewise insert altered amino acids at sites in RecA which are involved in the activation of RecA protein by binding small molecules or polynucleotides which metabolically regulate RecA protein.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=209931Documentos Relacionados
- Dual role for Escherichia coli RecA protein in SOS mutagenesis.
- RecA protein-dependent cleavage of UmuD protein and SOS mutagenesis.
- Involvement of the activated form of RecA protein in SOS mutagenesis and stable DNA replication in Escherichia coli.
- UmuD mutagenesis protein of Escherichia coli: overproduction, purification, and cleavage by RecA.
- Escherichia coli recA gene product inactivates phage lambda repressor.