anthramycin , an antitumor antibiotic produced by streptomyces refuineus , produces a well defined covalent adduct with dna and lies within the narrow groove of dna , attached through a thermal-labile covalent animal linkage to the exocyclic amino group of guanine , without detectable distortion of the helix ( petrusek , r. l. , anderson , g. l. , garner , t. f. , fannin , q. l. , kaplan , d. j. zimmer , s. g. , and hurley , l. h. ( 1981 ) biochemistry 20 , 1111-1119 ) .
C0000702
a
C0012854
dna