Both ATPase sites of Escherichia coli UvrA have functional roles in nucleotide excision repair

Journal Article · Sat Jun 15 04:00:00 EDT 1991 · Journal of Biological Chemistry; (United States)

OSTI ID:5506437

Thiagalingam, S; Grossman, L ^[1]

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1. Department of Biochemistry, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland (USA)

The roles of the two tandemly arranged putative ATP binding sites of Escherichia coli UvrA in UvrABC endonuclease-mediated excision repair were analyzed by site-directed mutagenesis and biochemical characterization of the representative mutant proteins. Evidence is presented that UvrA has two functional ATPase sites which coincide with the putative ATP binding motifs predicted from its amino acid sequence. The individual ATPase sites can independently hydrolyze ATP. The C-terminal ATPase site has a higher affinity for ATP than the N-terminal site. The invariable lysine residues at the ends of the glycine-rich loops of the consensus Walker type A motifs are indispensable for ATP hydrolysis. However, the mutations at these lysine residues do not significantly affect ATP binding. UvrA, with bound ATP, forms the most favored conformation for DNA binding. The initial binding of UvrA to DNA is chiefly at the undamaged sites. In contrast to the wild type UvrA, the ATPase site mutants bind equally to damaged and undamaged sites. Dissociation of tightly bound nucleoprotein complexes from the undamaged sites requires hydrolysis of ATP by the C-terminal ATPase site of UvrA. Thus, both ATP binding and hydrolysis are required for the damage recognition step enabling UvrA to discriminate between damaged and undamaged sites on DNA.

• OSTI ID: 5506437
• Journal Information: Journal of Biological Chemistry; (United States), Journal Name: Journal of Biological Chemistry; (United States) Vol. 266:17; ISSN JBCHA; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

560130* -- Radiation Effects on Microorganisms
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
AMINO ACID SEQUENCE
ATP-ASE
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL FUNCTIONS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA
DNA REPAIR
DOSE-RESPONSE RELATIONSHIPS
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
EXCISION REPAIR
HYDROLASES
KINETICS
MEMBRANE PROTEINS
MICROORGANISMS
MOLECULAR STRUCTURE
MUTANTS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PROTEINS
RADIATIONS
REACTION KINETICS
RECEPTORS
RECOVERY
REPAIR
ULTRAVIOLET RADIATION