5K7F
Crystal structure of apo AibR
Summary for 5K7F
| Entry DOI | 10.2210/pdb5k7f/pdb |
| Descriptor | Transcriptional regulator, TetR family, ACETATE ION (3 entities in total) |
| Functional Keywords | tetr like regulator, isovalerate, regulation, transcription |
| Biological source | Myxococcus xanthus (strain DK 1622) |
| Total number of polymer chains | 2 |
| Total formula weight | 51427.75 |
| Authors | Bock, T.,Volz, C.,Mueller, R.,Blankenfeldt, W. (deposition date: 2016-05-26, release date: 2016-12-21, Last modification date: 2024-05-08) |
| Primary citation | Bock, T.,Volz, C.,Hering, V.,Scrima, A.,Muller, R.,Blankenfeldt, W. 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. Nucleic Acids Res., 45:2166-2178, 2017 Cited by PubMed Abstract: 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. PubMed: 27940564DOI: 10.1093/nar/gkw1238 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.7 Å) |
Structure validation
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