5yum

Crystallographic structures of IlvN.Val/Ile complexes:Conformational selectivity for feedback inhibition of AHASs

spinqualitylabelsall models 5yum, resolution 2.43Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5yum is a 1 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.432Å Ligands: CO, ILE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ILVN_ECOLI Publication Abstract from PubMed Conformational factors that predicate selectivity for valine or isoleucine binding to IlvN leading to the regulation of aceto hydroxy acid synthase I (AHAS I) of Escherichia coli have been determined for the first time from high-resolution (1.9-2.43 A) crystal structures of IlvN.Val and IlvN.Ile complexes. The valine and isoleucine ligand binding pockets are located at the dimer interface. In the IlvN.Ile complex, among residues in the binding pocket, the side chain of Cys(43) is 2-fold disordered (chi1 angles of gauche(-) and trans). Only one conformation can be observed for the identical residue in the IlvN.Val complexes. In a reversal, the side chain of His(53), located at the surface of the protein, exhibits two conformations in the IlvN.Val complex. The concerted conformational switch in the side chains of Cys(43) and His(53) may play an important role in the regulation of the AHAS I holoenzyme activity. A significant result is the establishment of the subunit composition in the AHAS I holoenzyme by analytical ultracentrifugation. Solution nuclear magnetic resonance and analytical ultracentrifugation experiments have also provided important insights into the hydrodynamic properties of IlvN in the ligand-free and -bound states. The structural and biophysical data unequivocally establish the molecular basis for differential binding of the ligands to IlvN and a rationale for the resistance of IlvM to feedback inhibition by the branched-chain amino acids. Crystallographic Structures of IlvN.Val/Ile Complexes: Conformational Selectivity for Feedback Inhibition of Aceto Hydroxy Acid Synthases.,Bansal A, Karanth NM, Demeler B, Schindelin H, Sarma SP Biochemistry. 2019 Mar 29. doi: 10.1021/acs.biochem.9b00050. PMID:30887800 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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