1wrt
From Proteopedia
NMR STUDY OF APO TRP REPRESSOR
Structural highlights
FunctionTRPR_ECOLI This protein is an aporepressor. When complexed with L-tryptophan it binds the operator region of the trp operon (5'-ACTAGT-'3') and prevents the initiation of transcription. The complex also regulates trp repressor biosynthesis by binding to its regulatory region. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe solution structures of the trp-repressor from Escherichia coli in both the liganded (holo-) and unliganded (apo-) form, have been refined by restrained molecular dynamics with simulated annealing using the program XPLOR and additional experimental constraints. The ensemble of refined holorepressor structures have a root-mean-square deviation (r.m.s.d.) of 0.8 A relative to the average structure for the backbone of the dimer core (helices A, B, C, A', B', C') and 2.5 A for the helix-turn-helix DNA-binding domain (helices D and E). The corresponding values for the aporepressor are 0.9 A for the backbone of the ABC-dimer core and 3.2 A for the DE helix-turn-helix. The r.m.s.d. of the average structures from the corresponding crystal structures are 2.3 A for the holorepressor ABC core and 4.2 A for its DE region; 2.3 A for the aporepressor core and 5.5 A for its DE region. The relative disorder of the DNA-binding domain is reflected in a number of experimental parameters including substantially more rapid backbone proton exchange rates, exchange-limited relaxation times and crystallographic B-factors. The stabilizing effect of the L-Trp ligand is evident in these measurements, as it is in the higher precision of the holorepressor structure. Refined solution structures of the Escherichia coli trp holo- and aporepressor.,Zhao D, Arrowsmith CH, Jia X, Jardetzky O J Mol Biol. 1993 Feb 5;229(3):735-46. PMID:8433368[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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