The Agrobacterium tumefaciens Transcription Factor BlcR Is Regulated via Oligomerization
- IMCB-Singapore
The Agrobacterium tumefaciens BlcR is a member of the emerging isocitrate lyase transcription regulators that negatively regulates metabolism of {gamma}-butyrolactone, and its repressing function is relieved by succinate semialdehyde (SSA). Our crystal structure showed that BlcR folded into the DNA- and SSA-binding domains and dimerized via the DNA-binding domains. Mutational analysis identified residues, including Phe{sup 147}, that are important for SSA association; BlcR{sup F147A} existed as tetramer. Two BlcR dimers bound to target DNA and in a cooperative manner, and the distance between the two BlcR-binding sequences in DNA was critical for BlcR-DNA association. Tetrameric BlcR{sup F147A} retained DNA binding activity, and importantly, this activity was not affected by the distance separating the BlcR-binding sequences in DNA. SSA did not dissociate tetrameric BlcR{sup F147A} or BlcR{sup F147A}-DNA. As well as in the SSA-binding site, Phe{sup 147} is located in a structurally flexible loop that may be involved in BlcR oligomerization. We propose that SSA regulates BlcR DNA-binding function via oligomerization.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- NSFNIH
- OSTI ID:
- 1027652
- Journal Information:
- J. Biol. Chem., Vol. 286, Issue (23) ; 06, 2011; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- ENGLISH
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