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The AibR-isovaleryl coenzyme A regulator and its DNA binding site - a model for the regulation of alternative de novo isovaleryl coenzyme A biosynthesis in Myxococcus xanthus.
Bock, Tobias; Volz, Carsten; Hering, Vanessa; Scrima, Andrea; Müller, Rolf; Blankenfeldt, Wulf.
Affiliation
  • Bock T; Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
  • Volz C; Structural Biology of Autophagy, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
  • Hering V; Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
  • Scrima A; Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Centre for Infection Research, Saarland University, 66123 Saarbrücken, Germany.
  • Müller R; Structural Biology of Autophagy, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
  • Blankenfeldt W; Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Nucleic Acids Res ; 45(4): 2166-2178, 2017 02 28.
Article in En | MEDLINE | ID: mdl-27940564
Isovaleryl coenzyme A (IV-CoA) is an important building block of iso-fatty acids. In myxobacteria, IV-CoA is essential for the formation of signaling molecules involved in fruiting body formation. Leucine degradation is the common source of IV-CoA, but a second, de novo biosynthetic route to IV-CoA termed AIB (alternative IV-CoA biosynthesis) was recently discovered in M. xanthus. The AIB-operon contains the TetR-like transcriptional regulator AibR, which we characterize in this study. We demonstrate that IV-CoA binds AibR with micromolar affinity and show by gelshift experiments that AibR interacts with the promoter region of the AIB-operon once IV-CoA is present. We identify an 18-bp near-perfect palindromic repeat as containing the AibR operator and provide evidence that AibR also controls an additional genomic locus coding for a putative acetyl-CoA acetyltransferase. To elucidate atomic details, we determined crystal structures of AibR in the apo, the IV-CoA- and the IV-CoA-DNA-bound state to 1.7 Å, 2.35 Å and 2.92 Å, respectively. IV-CoA induces partial unfolding of an α-helix, which allows sequence-specific interactions between AibR and its operator. This study provides insights into AibR-mediated regulation and shows that AibR functions in an unusual TetR-like manner by blocking transcription not in the ligand-free but in the effector-bound state.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Transcription Factors / Binding Sites / Acyl Coenzyme A / Gene Expression Regulation, Bacterial / Myxococcus xanthus Type of study: Prognostic_studies Language: En Journal: Nucleic Acids Res Year: 2017 Document type: Article Affiliation country: Germany Country of publication: United kingdom

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Transcription Factors / Binding Sites / Acyl Coenzyme A / Gene Expression Regulation, Bacterial / Myxococcus xanthus Type of study: Prognostic_studies Language: En Journal: Nucleic Acids Res Year: 2017 Document type: Article Affiliation country: Germany Country of publication: United kingdom