Nucleic acid enzymes for cleaving DNA

Abstract

The present invention discloses nucleic acid enzymes capable of cleaving single-stranded DNA in a site specific manner.

I claim:  
     
         1 . A method for specifically cleaving a single-stranded DNA molecule, comprising the steps of: 
 (a) providing a first RNA molecule that is a group I intron that cleaves a second RNA molecule to leave a 3′-OH, said first RNA molecule having a deoxyribonuclease activity; and    (b) contacting said first RNA molecule with said single-stranded DNA molecule under conditions which allow said first RNA molecule to cause said single-stranded DNA molecule to be cleaved, said conditions including providing Mg 2+  ions and guanosine or guanosine triphosphate at a pH between about 6.0 and about 9.0 and a temperature between about 150C and about 60° C.    
     
     
         2 . The method of  claim 1 , further comprising providing said RNA molecule in a reaction medium at a concentration sufficient to cause cleavage of at least 1% of a population of the DNA molecules in an hour.  
     
     
         3 . The method of  claim 1 , further comprising providing said RNA molecule in a reaction medium at a concentration sufficient to cause cleavage of at least 10% of a population of the DNA molecules in an hour.  
     
     
         4 . The method of  claim 1 , wherein said RNA molecule comprises the portions of an RNA molecule of Tetrahymena having said deoxyribonuclease activity.  
     
     
         5 . The method of  claim 4 , wherein said RNA molecule is L-19, L-21, or an RNA molecule comprising the portions of L-19 having said deoxyribonuclease activity.  
     
     
         6 . The method of  claim 1 , wherein said RNA molecule comprises a binding site for single-stranded DNA, which binding site is complementary to nucleotides adjacent to a cleavage site on said single-stranded DNA molecule.