Binding affinity and mode of distamycin A with A/T stretches in double-stranded DNA: Importance of the terminal A/T residues

作者：Asagi Mariko; Toyama Akira; Takeuchi Hideo^*

来源：Biophysical Chemistry, 2010, 149(1-2): 34-39.

DOI：10.1016/j.bpc.2010.03.014

• Distamycin A
• DNA
• Circular dichroism
• Binding mode
• Singular value decomposition

Distamycin A (Dst) is an antibiotic which binds to the minor groove of double-stranded DNA at A/T-rich regions. We have examined the affinity and mode of Dst binding to DNA duplexes containing a conserved A/T core and variable terminal A/T regions by using circular dichroism spectroscopy. The observed circular dichroism spectra were analyzed by singular value decomposition and fitted to a two-step binding model. The result clearly shows a correlation between the affinity for Dst and the preference for Dst-DNA 1:1 binding over 2:1 binding. The Air stretches that prefer 1:1 binding form high-affinity 1:1 complexes, whereas those preferring 2:1 binding form stable 2:1 complex with low overall affinities. The terminal Aft residues of the Dst binding region play an important role in the stabilization/destabilization of the 1:1 and 2:1 complexes, resulting in a terminal residue-dependent variation of the binding affinity and the binding mode preference.

• 出版日期2010-6