Determination of distamycin-A binding modes by NMR

摘要: The application of NMR to characterization of the binding of distamycin A to DNA oligomers is discussed. The orientational preference has been determined for single distamycins binding to A-T rich sequences. In sites containing more than the minimal four A-T pairs there is evidence for a sliding transfer of the drug between neighboring binding sites at a high rate. In sites containing five and six A-T pairs there is a second binding mode in which two distamycins bind side-by-side in the minor groove, in close contact with one another in addition to the walls of the groove. There also appears to be a sliding transfer of drugs within the 2:1 complex when the binding site is more than the minimal five A-T pairs.