Structural highlights
Function
[LEXA_ECOLI] Represses a number of genes involved in the response to DNA damage (SOS response), including recA and lexA. Binds to the 16 bp palindromic sequence 5'-CTGTATATATATACAG-3'. In the presence of single-stranded DNA, RecA interacts with LexA causing an autocatalytic cleavage which disrupts the DNA-binding part of LexA, leading to derepression of the SOS regulon and eventually DNA repair.[1] [2]
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 PubMed
The structure of the 84 residue DNA binding domain of the Escherichia coli LexA repressor has been determined from NMR data using distance geometry and restrained molecular dynamics. The assignment of the 1H NMR spectrum of the molecule, derived from 2- and 3-D homonuclear experiments, is also reported. A total of 613 non-redundant distance restraints were used to give a final family of 28 structures. The structured region of the molecule consisted of residues 4-69 and yielded a r.m.s. deviation from an average of 0.9 A for backbone and 1.6 A for all heavy atoms. The structure contains three regular alpha-helices at residues 6-21 (I), 28-35 (II) and 41-52 (III), and an antiparallel beta-sheet at residues 56-58 and 66-68. Helices II and III form a variant helix-turn-helix DNA binding motif, with an unusual one residue insert at residue 38. The topology of the LexA DNA binding domain is found to be the same as for the DNA binding domains of the catabolic activator protein, human histone 5, the HNF-3/fork head protein and the Kluyveromyces lactis heat shock transcription factor.
Solution structure of the LexA repressor DNA binding domain determined by 1H NMR spectroscopy.,Fogh RH, Ottleben G, Ruterjans H, Schnarr M, Boelens R, Kaptein R EMBO J. 1994 Sep 1;13(17):3936-44. PMID:8076591[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Little JW, Mount DW, Yanisch-Perron CR. Purified lexA protein is a repressor of the recA and lexA genes. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4199-203. PMID:7027255
- ↑ Brent R, Ptashne M. Mechanism of action of the lexA gene product. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4204-8. PMID:7027256
- ↑ Fogh RH, Ottleben G, Ruterjans H, Schnarr M, Boelens R, Kaptein R. Solution structure of the LexA repressor DNA binding domain determined by 1H NMR spectroscopy. EMBO J. 1994 Sep 1;13(17):3936-44. PMID:8076591
