Cobaltabis(dicarbollide) Interaction with DNA Resolved at the Atomic Scale

Area of Science:

• Biochemistry
• Computational Chemistry
• Nanomedicine

Background:

• Boron neutron capture therapy (BNCT) offers a promising cancer treatment strategy.
• Nontoxic, boron-rich drugs are crucial for BNCT, needing efficient cancer cell delivery.
• The metallacarborane [COSAN]- is a candidate drug, but its DNA interaction is unclear.

Purpose of the Study:

• To elucidate the DNA/[COSAN]- interaction mechanism, strength, and timescale at the atomistic level.
• To quantify the binding free energy of [COSAN]- to DNA.
• To resolve contradictory findings regarding DNA interaction modes.

Main Methods:

• Microsecond molecular dynamics simulations.
• Hybrid quantum mechanics/molecular mechanics (QM/MM) simulations.
• Absolute binding free energy calculations.

Main Results:

• DNA/[COSAN]- interaction is highly sensitive to ionic strength.
• Weak DNA major groove binding (ΔGbind = -2.49 kcal/mol) observed at high NaCl concentrations.
• Binding is primarily driven by dihydrogen B-H···H-N bonds; intercalation is unlikely.

Conclusions:

• [COSAN]- exhibits weak, ionic-strength-dependent DNA binding.
• The major groove binding mechanism, not intercalation, is favored under specific conditions.
• Further research is needed to optimize [COSAN]- for BNCT applications.