Type I restriction enzyme EcoR124I/EcoR124II endonuclease subunit

UniProtKB accession:  P10486

Grouped By:  Matching UniProtKB accession

UniProtKB description:  The restriction (R) subunit of a type I restriction enzyme that recognizes 5'-GAAN(6)RTCG-3' (for EcoR124I) and 5'-GAAN(7)RTCG-3' (for EcoR124II) and cleaves a random distance away (PubMed:2784505). Subunit R is required for both nuclease and ATPase activities, but not for modification (Probable) (PubMed:12654995). After locating an unmethylated recognition site, the enzyme complex serves as a molecular motor that translocates DNA in an ATP-dependent manner until a collision occurs that triggers cleavage (PubMed:15300241). The enzyme undergoes major structural changes to bring the motor domains into contact with DNA, allowing DNA translocation. This prevents DNA access to the catalytic domains of both the R and M subunits, preventing both restriction and methylation (PubMed:32483229). The R(1)M(2)S(1) complex translocates an average of 555 bp/second on nicked DNA; the R(2)M(2)S(1) complex translocates at double that speed (PubMed:15300241). The 2 R subunit motors are independent and track along the helical pitch of the DNA, inducing positive supercoiling ahead of themselves (PubMed:15300241).