The RecB subunit of the Escherichia coli RecBCD enzyme couples ATP hydrolysis to DNA unwinding. |
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| Authors: | P E Boehmer P T Emmerson |
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| Institution: | Department of Biochemistry and Genetics, University of Newcastle upon Tyne, Medical School, United Kingdom. |
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| Abstract: | The RecB subunit of the Escherichia coli RecBCD enzyme has previously been reported to possess DNA-dependent ATPase activity (Hickson, I. D., Robson, C. N., Atkinson, K. E., Hutton, L., and Emmerson, P. T. (1985) J. Biol. Chem. 260, 1224-1229). Here we demonstrate that a specific interaction between RecB protein and ATP can also be shown by photoaffinity labeling with the ATP analogue 8-azido-ATP. Furthermore, the capacity of the RecB protein to support ATP hydrolysis varies with the structure and length of the DNA cofactor. Single-stranded linear and circular DNA are markedly better in promoting ATP hydrolysis than duplex DNA. The purified RecB protein can function as a DNA helicase, displacing oligonucleotides annealed to viral M13 DNA in an ATP-dependent and orientation-specific manner. |
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