>gnl|CDD|119397 cd06529, S24_LexA-like, Peptidase S24 LexA-like proteins are involved in the SOS response leading to the repair of single-stranded DNA within the bacterial cell. This family includes: the lambda repressor CI/C2 family and related bacterial prophage repressor proteins; LexA (EC 3.4.21.88), the repressor of genes in the cellular SOS response to DNA damage; MucA and the related UmuD proteins, which are lesion-bypass DNA polymerases, induced in response to mitogenic DNA damage; RulA, a component of the rulAB locus that confers resistance to UV, and RuvA, which is a component of the RuvABC resolvasome that catalyzes the resolution of Holliday junctions that arise during genetic recombination and DNA repair. The LexA-like proteins contain two-domains: an N-terminal DNA binding domain and a C-terminal domain (CTD) that provides LexA dimerization as well as cleavage activity. They undergo autolysis, cleaving at an Ala-Gly or a Cys-Gly bond, separating the DNA-binding domain from the rest of the protein. In the presence of single-stranded DNA, the LexA, UmuD and MucA proteins interact with RecA, activating self cleavage, thus either derepressing transcription in the case of LexA or activating the lesion-bypass polymerase in the case of UmuD and MucA. The LexA proteins are serine proteases that carry out catalysis using a serine/lysine dyad instead of the prototypical serine/histidine/aspartic acid triad found in most serine proteases. LexA sequence homologs are found in almost all of the bacterial genomes sequenced to date, covering a large number of phyla, suggesting both, an ancient origin and a widespread distribution of lexA and the SOS response.. Length = 81

 Score = 39.1 bits (92), Expect = 0.001
 Identities = 20/75 (26%), Positives = 30/75 (40%), Gaps = 25/75 (33%)

Query: 44  SMIPTLLVGDYIIVNKFSYGYSKYSFPFSYNLFNGRIFNNQPRRGDVVVFRYPKDPSIDY 103
           SM PT+  GD ++V+                       ++ PR GD+VV R   +     
Sbjct: 9   SMEPTIPDGDLVLVDP----------------------SDTPRDGDIVVARLDGEL---T 43

Query: 104 VKRVIGLPGDRISLE 118
           VKR+    G R+ L 
Sbjct: 44  VKRLQRRGGGRLRLI 58