Steady-state kinetic analysis of ATP hydrolysis by the B protein of bacteriophage mu. Involvement of protein oligomerization in the ATPase cycle.
The DNA strand-transfer reaction of bacteriophage Mu requires Mu B protein and ATP for high efficiency. These factors facilitate the capture of target DNA by the donor protein-DNA complex. To understand the mechanism of the Mu B ATPase cycle in the Mu DNA strand-transfer reaction, we undertook a steady-state kinetic analysis of Mu B ATPase. The results reveal complex properties of the ATPase activity; Mu B protein oligomerizes in the presence of ATP, and ATP hydrolysis by the Mu B ATPase is stimulated by the protein oligomerization and shows a positive cooperativity with respect to ATP concentration. Mu B ATPase activity is also modulated by DNA and Mu A protein. DNA alone suppresses the catalytic activity of Mu B ATPase, whereas DNA enhances the apparent binding affinity for ATP. In the presence of Mu A protein together with DNA, however, the catalytic activity is greatly stimulated. Based on these results, we propose a working hypothesis in which oligomerization of Mu B protein plays a key role in its ATPase cycle.
Adzuma
K
K
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Mizuuchi
K
K
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D010583:Bacteriophage mu / Q000378:metabolism*; D002384:Catalysis; D003432:Cross-Linking Reagents; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D010957:Plasmids; D011108:Polymers; D014764:Viral Proteins
D003432:Cross-Linking Reagents; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C050938:Mu B protein, bacteriophage; D011108:Polymers; D014764:Viral Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases