▁target ▁de amin ated ▁bases ▁cannot ▁target ▁th ym ine ▁( it ▁being ▁one ▁of ▁the ▁regular ▁four ▁bases ▁in ▁DNA ). ▁ ▁The ▁components ▁of ▁the ▁system ▁are ▁Mut S , ▁which ▁bind s ▁to ▁the ▁GT ▁mismatch , ▁the ▁VS R ▁end on uc lease , ▁which ▁cut s ▁the ▁DNA , ▁and ▁Mut L , ▁which ▁rec ruits ▁the ▁U vr D ▁hel ic ase . ▁ ▁VS R ▁( very ▁short ▁patch ▁repair ) ▁end on uc leases ▁occur ▁in ▁a ▁variety ▁of ▁b acter ia . ▁They ▁work ▁by ▁cutting , ▁or ▁rather , ▁making ▁a ▁nick ▁in ▁DNA ▁if ▁the ▁base ▁pair ▁is ▁mut ated ▁or ▁dam aged . ▁ ▁Function ▁Mut ations ▁in ▁the ▁base ▁pairs ▁of ▁DNA ▁can ▁be ▁harm ful ▁to ▁the ▁organ ism . ▁ ▁In ▁particular , ▁C ▁to ▁T ▁mut ations ▁occur ▁quite ▁often ▁due ▁to ▁m eth yl ation ▁of ▁c yt os ine . ▁Hence , ▁the ▁VS R ▁end on uc leases ▁have ▁a ▁function ▁to ▁protect ▁the ▁cell ▁from ▁damage ▁caused ▁by ▁mut ated ▁DNA . ▁ ▁Mechan ism ▁VS R ▁recogn ises ▁a ▁T G ▁mismatch ed ▁base ▁pair , ▁generated ▁after ▁sp ont aneous ▁de am ination ▁of ▁m eth yl ated ▁c yt os ines , ▁and ▁it ▁creates ▁a ▁nick ▁ ▁on ▁a ▁single ▁str and ▁by ▁cle aving ▁the ▁ph osph ate ▁back bone ▁on ▁the ▁ 5 ' ▁side ▁of ▁the ▁th ym ine . ▁Then ▁DNA ▁Pol ym er ase