Protein Domain : EcoEI R protein C-terminal domain IPR013670

Type	Domain
Description	There are four classes of restriction endonucleases: types I, II,III and IV. All types of enzymes recognise specific short DNA sequences and carry out the endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'-phosphates. They differ in their recognition sequence, subunit composition, cleavage position, and cofactor requirements [ , ], as summarised below:Type I enzymes ( ) cleave at sites remote from recognition site; require both ATP and S-adenosyl-L-methionine to function; multifunctional protein with both restriction and methylase ( ) activities. Type II enzymes ( ) cleave within or at short specific distances from recognition site; most require magnesium; single function (restriction) enzymes independent of methylase. Type III enzymes ( ) cleave at sites a short distance from recognition site; require ATP (but doesn't hydrolyse it); S-adenosyl-L-methionine stimulates reaction but is not required; exists as part of a complex with a modification methylase methylase ( ). Type IV enzymes target methylated DNA.This entry represents the C-terminal domain found in both the R subunit of type I enzymes and the Res subunit of type III enzymes. The type I enzymes include EcoEI, which recognises 5'-GAGN(7)ATGC-3; the R protein (HsdR) is required for both nuclease and ATPase activity [ , ].
Short Name	EcoEI_R_C_dom