Inhibition of RecA protein by the Escherichia coli RecX protein: modulation by the RecA C terminus and filament functional state

• Published in: The Journal of biological chemistry Vol. 279; no. 51; pp. 52991 - 52997
• Main Authors: Drees, Julia C, Lusetti, Shelley L, Cox, Michael M
• Format: Journal Article
• Language: English
• Published: United States 17.12.2004
• Subjects: Adenosine Triphosphatases - chemistry; Adenosine Triphosphate - chemistry; Bacterial Proteins - chemistry; Bacterial Proteins - physiology; Buffers; Cloning, Molecular; DNA - chemistry; DNA, Single-Stranded - chemistry; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Escherichia coli - metabolism; Escherichia coli - physiology; Escherichia coli Proteins - physiology; Gene Expression Regulation, Bacterial; Hydrolysis; Ions; Magnesium - chemistry; Point Mutation; Protein Structure, Tertiary; Rec A Recombinases - antagonists & inhibitors; Rec A Recombinases - chemistry; Time Factors
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M409050200

The RecX protein is a potent inhibitor of RecA activities. We identified several factors that affect RecX-RecA interaction. The interaction is enhanced by the RecA C terminus and by significant concentrations of free Mg(2+) ion. The interaction is also enhanced by an N-terminal His(6) tag on the RecX protein. We conclude that RecX protein interacts most effectively with a RecA functional state designated A(o) and that the RecA C terminus has a role in modulating the interaction. We further identified a C-terminal point mutation in RecA protein (E343K) that significantly alters the interaction between RecA and RecX proteins.