plasmids carrying 24- or 32-base-pair inserts of alternating ( dg-dc ) residues were used to analyze the level of methylation of the g-c-g-c sites by hha i dna methyltransferase and their cleavage by hha i endonuclease in the b-dna or z-dna conformation .
C0025723
methylation
C0012873
dna