FEATURES OF DNA RECOGNITION FOR ORIENTED BINDING AND CLEAVAGE BY CALICHEAMICIN

[摘要] The cleavage by calicheamicin gamma(1)(I) of duplex DNA containing four or more contiguous adenines on one strand proceeds through C5' hydrogen abstraction at the penultimate thymidine at the 5' end of the T-tract. Cleavage of longer A-tracts (A(16) and A(42)) results, in addition to the primary cleavage site, in a cascade of weaker cuts that persists until the four or fifth nucleotide from the 5' end of the A-tract. Cleavage by calicheamicin gamma(1)(I) of free DNA known to form nucleosomes shows a periodic pattern that is correlated to structural periodicities found in the DNA. We suggest that calicheamicin recognizes and cleaves sequences of DNA that have a narrow minor groove, and regions of DNA that may have a propensity for helix deformation.

[发布日期] 1994-01-31