DNA sequence recognition of thiazole-containing cross-linked polyamides can be favored

Area of Science:

• Chemical Biology
• Molecular Biology
• Biochemistry

Background:

• Polyamides are molecules that can bind to DNA.
• Cross-linking polyamides can alter their DNA binding properties.
• Understanding polyamide-DNA interactions is crucial for developing new therapeutic agents.

Purpose of the Study:

• To investigate the DNA binding specificity of cross-linked thiazolated polyamides.
• To evaluate the inhibitory effect of these polyamides on DNA gyrase activity.
• To explore the role of specific DNA sequences, such as T-A steps, in polyamide binding.

Main Methods:

• Circular dichroism (CD) titration experiments were used to assess DNA binding.
• Footprinting assays provided complementary data on binding interactions.
• In vitro biochemical assays measured the inhibition of DNA gyrase activity.

Main Results:

• Cross-linked polyamide dimers exhibited higher DNA sequence specificity than monomers.
• The Th-Py-Py dimer preferentially bound to AT-rich sequences, while Th-Im-Py bound to sequences with GC pairs.
• Both dimers showed strong affinity for sequences containing T-A steps.
• Polyamide dimers effectively inhibited DNA gyrase activity, with Th-Py-Py being the most potent.

Conclusions:

• Cross-linked thiazolated polyamides demonstrate tunable DNA sequence recognition.
• The T-A DNA step plays a significant role in the binding of these polyamides to the DNA minor groove.
• These polyamides show potential as inhibitors of DNA gyrase and may have therapeutic applications.