UvrB Domain 4, an Autoinhibitory Gate for Regulation of DNA Binding and ATPase Activity

• Published in: The Journal of biological chemistry Vol. 281; no. 22; pp. 15227 - 15237
• Main Authors: Wang, Hong, DellaVecchia, Matthew J., Skorvaga, Milan, Croteau, Deborah L., Erie, Dorothy A., Van Houten, Bennett
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 02.06.2006; American Society for Biochemistry and Molecular Biology
• Subjects: Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; Amino Acid Sequence; Bacillus; Bacillus - genetics; Bacillus - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Base Sequence; Dimerization; DNA Damage; DNA Repair; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; Kinetics; Models, Biological; Molecular Sequence Data; Protein Structure, Quaternary; Protein Structure, Tertiary; Sequence Homology, Amino Acid
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M601476200

UvrB, a central DNA damage recognition protein in bacterial nucleotide excision repair, has weak affinity for DNA, and its ATPase activity is activated by UvrA and damaged DNA. Regulation of DNA binding and ATP hydrolysis by UvrB is poorly understood. Using atomic force microscopy and biochemical assays, we found that truncation of domain 4 of Bacillus caldotenax UvrB (UvrBΔ4) leads to multiple changes in protein function. Protein dimerization decreases with an ∼8-fold increase of the equilibrium dissociation constant and an increase in DNA binding. Loss of domain 4 causes the DNA binding mode of UvrB to change from dimer to monomer, and affinity increases with the apparent dissociation constants on nondamaged and damaged single-stranded DNA decreasing 22- and 14-fold, respectively. ATPase activity by UvrBΔ4 increases 14- and 9-fold with and without single-stranded DNA, respectively, and UvrBΔ4 supports UvrA-independent damage-specific incision by Cho on a bubble DNA substrate. We propose that other than its previously discovered role in regulating protein-protein interactions, domain 4 is an autoinhibitory domain regulating the DNA binding and ATPase activities of UvrB.