9f14

The crystal structure of full length tetramer CysB from Klebsiella aerogenes in complex with N-acetylserine

spinqualitylabelsall models 9f14, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9f14 is a 2 chain structure with sequence from Klebsiella aerogenes. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3Å Ligands: SAC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CYSB_KLEPN This protein is a positive regulator of gene expression for the cysteine regulon. The inducer for CysB is N-acetylserine. Thiosulfate and sulfide act as anti-inducers. Publication Abstract from PubMed In Escherichia coli and Salmonella typhimurium, cysteine biosynthesis requires the products of 20 or more cys genes co-ordinately regulated by CysB. Under conditions of sulphur limitation and in the presence of the inducer, N-acetylserine, CysB binds to cys promoters and activates the transcription of the downstream coding sequences. CysB is a homotetramer, comprising an N-terminal DNA binding domain (DBD) and a C-terminal effector binding domain (EBD). The crystal structure of a dimeric EBD fragment of CysB from Klebsiella aerogenes revealed a protein fold similar to that seen in Lac repressor but with a different symmetry in the dimer so that the mode of DNA binding was not apparent. To elucidate the subunit arrangement in the tetramer, we determined the crystal structure of intact CysB in complex with N-acetylserine. The tetramer has two subunit types that differ in the juxtaposition of their winged helix-turn-helix DNA binding domains with respect to the effector binding domain. In the assembly, the four EBDs form a core with the DNA binding domains arranged in pairs on the surface. N-acetylserine makes extensive polar interactions in an enclosed binding site, and its binding is accompanied by substantial conformational rearrangements of surrounding residues that are propagated to the protein surface where they appear to alter the arrangement of the DNA binding domains. The results are (i) discussed in relation to the extensive mutational data available for CysB and (ii) used to propose a structural mechanism of N-acetylserine induced CysB activation. The Structure of the LysR-type Transcriptional Regulator, CysB, Bound to the Inducer, N-acetylserine.,Verschueren KHG, Dodson EJ, Wilkinson AJ Eur Biophys J. 2024 Jul 8. doi: 10.1007/s00249-024-01716-w. PMID:38976018 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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