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Molybdate-activated form of ModE from Escherichia coli
Structural highlights
FunctionMODE_ECOLI The ModE-Mo complex acts as a repressor of the modABC operon, involved in the transport of molybdate. Upon binding molybdate, the conformation of the protein changes, promoting dimerization of ModE-Mo. The protein dimer is then competent to bind a DNA region, upstream of the modABC operon, which contains an 8-base inverted repeat 5'-TAACGTTA-3' flanked by two CAT boxes. Acts also as an enhancer of the expression of genes coding for molybdoenzymes, both directly and indirectly. ModE also interacts with tungstate. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedModE is a bacterial transcriptional regulator that orchestrates many aspects of molybdenum metabolism by binding to specific DNA sequences in a molybdate-dependent fashion. We present the crystal structure of Escherichia coli ModE in complex with molybdate, which was determined at 2.75A from a merohedrally twinned crystal (twin fraction approximately 0.30) with space group P4(3). We now have structures of ModE in both its "switched on" (ligand-bound) and "switched off" (apo) states. Comparison with the apo structure shows that ligand binding leads to extensive conformational changes not only in the molybdate-binding domain, but also in the DNA-binding domain. The most obvious difference is the loss of the pronounced asymmetry between the two chains of the ModE dimer, which had been a characteristic property of the apo structure. Another major change concerns the relative orientation of the two DNA-interacting winged helix-turn-helix motifs. Manual docking of an idealized DNA structure suggests that this conformational change should improve DNA binding of the activated molybdate-bound ModE. Crystal structure of activated ModE reveals conformational changes involving both oxyanion and DNA-binding domains.,Schuttelkopf AW, Boxer DH, Hunter WN J Mol Biol. 2003 Feb 21;326(3):761-7. PMID:12581638[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
