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?cl38903: RMtype1_S_TRD-CR_like Superfamily
 
Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR) and similar domains The restriction-modification (RM) system S subunit generally consists of two variable target recognition domains (TRD1 and 2) and two conserved regions (CR1 and CR2) which separate the TRDs. The TRDs each bind to different specific sequences in the DNA. RM systems protect a bacterial cell against invasion of foreign DNA by endonucleolytic cleavage of DNA that lacks a site specific modification. The host genome is protected from cleavage by methylation of specific nucleotides in the target sites. In type I systems, both restriction and modification activities are present in one heteromeric enzyme complex composed of one DNA specificity (S) subunit (this family), two modification (M) subunits and two restriction (R) subunits. This superfamily represents a single TRD-CR unit; in addition to type I TRD-CR units, it includes RMtype1_S_TRD-CR_like domains of various putative Helicobacter type II restriction enzymes and methyltransferases, such as Hci611ORFHP and HfeORF12890P, as well as TRD-CR-like sequence-recognition domains of the M subunit of putative type I DNA methyltransferase such as M2.CinURNWORF2828P and M.Mae7806ORF3969P. |
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Jiyao W et al.(2023). "The conserved domain database in 2023.",