Biophysical characterizations of human mitochondrial transcription factor A and its binding to tumor suppressor p53

Wong, TS;Rajagopalan, S;Freund, SM;Rutherford, TJ;Andreeva, A;Townsley, FM;Petrovich, M;Fersht, AR

[Wong, Tuck Seng; Rajagopalan, Sridharan; Freund, Stefan M.; Rutherford, Trevor J.; Andreeva, Antonina; Townsley, Fiona M.; Petrovich, Miriana; Fersht, Alan R.] MRC, Ctr Prot Engn, Cambridge CB2 0QH, England.
[Wong, Tuck Seng] Xian JiaoTong Liverpool Univ, Suzhou 215123, Jiangsu, Peoples R China.


Volume:37 Issue:20Pages:6765-6783


Publication Year:2009




Latest Impact Factor:16.971

Document Type:Journal Article



Human mitochondrial transcription factor A (TFAM) is a multi-functional protein, involved in different aspects of maintaining mitochondrial genome integrity. In this report, we characterized TFAM and its interaction with tumor suppressor p53 using various biophysical methods. DNA-free TFAM is a thermally unstable protein that is in equilibrium between monomers and dimers. Self-association of TFAM is modulated by its basic C-terminal tail. The DNA-binding ability of TFAM is mainly contributed by its first HMG-box, while the second HMG-box has low-DNA-binding capability. We also obtained backbone resonance assignments from the NMR spectra of both HMG-boxes of TFAM. TFAM binds primarily to the N-terminal transactivation domain of p53, with a K-d of 1.95 +/- 0.19 mu M. The C-terminal regulatory domain of p53 provides a secondary binding site for TFAM. The TFAM-p53-binding interface involves both TAD1 and TAD2 sub-domains of p53. Helices alpha 1 and alpha 2 of the HMG-box constitute the main p53-binding region. Since both TFAM and p53 binds preferentially to distorted DNA, the TFAM-p53 interaction is implicated in DNA damage and repair. In addition, the DNA-binding mechanism of TFAM and biological relevance of the TFAM-p53 interaction are discussed.

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