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Publication Abstract from PubMed

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(147), that are important for SSA association; BlcR(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(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(F147A) or BlcR(F147A)-DNA. As well as in the SSA-binding site, Phe(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.

The Agrobacterium tumefaciens Transcription Factor BlcR Is Regulated via Oligomerization.,Pan Y, Fiscus V, Meng W, Zheng Z, Zhang LH, Fuqua C, Chen L J Biol Chem. 2011 Jun 10;286(23):20431-40. Epub 2011 Apr 4. PMID:21467043^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.