2xdi
Tryptophan repressor with L75F mutation in its apo form (no L- tryptophan bound)
Structural highlights
Function[TRPR_ECO57] 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 (By similarity). 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 PubMedL75F-TrpR is a temperature-sensitive mutant of the tryptophan repressor protein of Escherichia coli in which surface-exposed residue leucine 75 in the DNA binding domain is replaced with phenylalanine. Biochemical and biophysical studies had suggested global alterations in dynamics for L75F-TrpR, although the structure was apparently similar to that of wild-type TrpR. Herein, we report the three-dimensional solution structure of apo-L75F-TrpR determined by multidimensional ((1)H, (15)N, and (13)C) solution NMR spectroscopy. An ensemble of structures was generated from 769 unique NOE-based distance restraints, 68 dihedral angle restraints, and 62 hydrogen bond distance restraints. Apo-L75F-TrpR exhibits a three-dimensional (3D) fold very similar to that of apo-WT-TrpR, with a dimeric core of four alpha-helices (A-C and F) from each subunit, and less well-defined D and E helical regions of the DNA binding domains. Despite their many similarities, wild-type and mutant proteins display significant chemical shift differences, one cluster of which is in the B-C turn, too distant to be ascribed solely to ring current effects from Phe75. Differences in NOE patterns and amide proton exchange rates are also observed in the B-C turn region. The data provide evidence that this point mutation exerts local effects on structure and stability in the DNA binding domain, and propagates long-range effects through the tertiary structure. Three-dimensional solution NMR structure of Apo-L75F-TrpR, a temperature-sensitive mutant of the tryptophan repressor protein.,Tyler R, Pelczer I, Carey J, Copie V Biochemistry. 2002 Oct 8;41(40):11954-62. PMID:12356295[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||
