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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                ....*....|....*....|....*....|....*....|
gi 24664648  70 PFNASERFVTILDSLDARVEKLRKDALNLQEKKDYLLMSM 109
Cdd:cd17496 135 PLEEQKRIVAILDPLDEKIDKNKQEIEKLEELRDTLLPKL 174

Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR), similar to Bacillus licheniformis S subunit (S1.BliBORF2384P) TRD1-CR1 and Chlorobium tepidum TLS S subunit (S.CteTORF675P) TRD1-CR1; The recognition sequences for Bacillus licheniformis S subunit (S1.BliBORF2384P) and Chlorobium tepidum TLS S subunit (S.CteTORF675P) are undetermined. The restriction-modification (RM) system S subunit 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 enzyme complex composed of one DNA specificity (S) subunit (this family), two modification (M) subunits and two restriction (R) subunits. This model contains both TRD1-CR1 and TRD2-CR2. This subfamily of TRD-CR's shows similarity to TRD1-CR1 of Aminobacterium colombiense DSM 12261 S subunit (S.Aco12261I), which recognizes 5'... GCANNNNNNTGT ... 3'. This subfamily may also include TRD-CR-like sequence-recognition domains of various type II restriction enzymes and methyltransferases and type I DNA methyltransferases.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|
gi 24664648  70 PFNASERFVTILDSLDARVEKLRKDALNLQEKKDYLLMSM 109
Cdd:cd17496 135 PLEEQKRIVAILDPLDEKIDKNKQEIEKLEELRDTLLPKL 174

Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR), similar to Bacillus licheniformis S subunit (S1.BliBORF2384P) TRD1-CR1 and Chlorobium tepidum TLS S subunit (S.CteTORF675P) TRD1-CR1; The recognition sequences for Bacillus licheniformis S subunit (S1.BliBORF2384P) and Chlorobium tepidum TLS S subunit (S.CteTORF675P) are undetermined. The restriction-modification (RM) system S subunit 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 enzyme complex composed of one DNA specificity (S) subunit (this family), two modification (M) subunits and two restriction (R) subunits. This model contains both TRD1-CR1 and TRD2-CR2. This subfamily of TRD-CR's shows similarity to TRD1-CR1 of Aminobacterium colombiense DSM 12261 S subunit (S.Aco12261I), which recognizes 5'... GCANNNNNNTGT ... 3'. This subfamily may also include TRD-CR-like sequence-recognition domains of various type II restriction enzymes and methyltransferases and type I DNA methyltransferases.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|
gi 24664648  70 PFNASERFVTILDSLDARVEKLRKDALNLQEKKDYLLMSM 109
Cdd:cd17496 135 PLEEQKRIVAILDPLDEKIDKNKQEIEKLEELRDTLLPKL 174