4xxh

TREHALOSE REPRESSOR FROM ESCHERICHIA COLI

spinqualitylabelsall models 4xxh, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4xxh is a 2 chain structure with sequence from Escherichia coli K-12. This structure supersedes the now removed PDB entry 1byk. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Ligands: G6P, GLC, PRD_900039 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRER_ECOLI Repressor of the treBC operon. Binds trehalose 6-phosphate as an inducer. Publication Abstract from PubMed The crystal structure of the Escherichia coli trehalose repressor (TreR) in a complex with its inducer trehalose-6-phosphate was determined by the method of multiple isomorphous replacement (MIR) at 2.5 A resolution, followed by the structure determination of TreR in a complex with its noninducer trehalose at 3.1 A resolution. The model consists of residues 61 to 315 comprising the effector binding domain, which forms a dimer as in other members of the LacI family. This domain is composed of two similar subdomains each consisting of a central beta-sheet sandwiched between alpha-helices. The effector binding pocket is at the interface of these subdomains. In spite of different physiological functions, the crystal structures of the two complexes of TreR turned out to be virtually identical to each other with the conformation being similar to those of the effector binding domains of the LacI and PurR in complex with their effector molecules. According to the crystal structure, the noninducer trehalose binds to a similar site as the trehalose portion of trehalose-6-phosphate. The binding affinity for the former is lower than for the latter. The noninducer trehalose thus binds competitively to the repressor. Unlike the phosphorylated inducer molecule, it is incapable of blocking the binding of the repressor headpiece to its operator DNA. The ratio of the concentrations of trehalose-6-phosphate and trehalose thus is used to switch between the two alternative metabolic uses of trehalose as an osmoprotectant and as a carbon source. Crystal structure of the effector-binding domain of the trehalose-repressor of Escherichia coli, a member of the LacI family, in its complexes with inducer trehalose-6-phosphate and noninducer trehalose.,Hars U, Horlacher R, Boos W, Welte W, Diederichs K Protein Sci. 1998 Dec;7(12):2511-21. PMID:9865945 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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