Protein Family Models

This is the DNA binding domain of the LexA SOS regulon repressor which prevents expression of DNA repair proteins. The aligned region contains a variant form of the helix-turn-helix DNA binding motif [1]. This domain is found associated with Pfam:PF00717 the auto-proteolytic domain of LexA EC:3.4.21.88. [1]. 8076591. 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;13:3936-3944. (from Pfam)

Date:

2024-10-16

Date:

2024-08-14

transcriptional repressor LexA represses a number of genes involved in the response to DNA damage (SOS response), including recA and lexA

Date:

2022-12-08

LexA acts as a homodimer to repress a number of genes involved in the response to DNA damage (SOS response), including itself and RecA. RecA, in the presence of single-stranded DNA, acts as a co-protease to activate a latent autolytic protease activity (EC 3.4.21.88) of LexA, where the active site Ser is part of LexA. The autolytic cleavage site is an Ala-Gly bond in LexA (at position 84-85 in E. coli LexA; this sequence is replaced by Gly-Gly in Synechocystis). The cleavage leads to derepression of the SOS regulon and eventually to DNA repair. LexA in Bacillus subtilis is called DinR. LexA is much less broadly distributed than RecA.

Gene:

lexA

Date:

2024-06-12