Development and Applications of the ReaxFF Reactive Force Field for Biological Systems
Chapter-style overview of ReaxFF applications to biological and biomolecular problems, with emphasis on parameterizations aimed at RNA/DNA chemistry, Zn–imidazole protonation, and peptide-bond hydrolysis (including Cu(II) catalysis), illustrated with reactive MD case studies compared to DFT where reported.
Summary¶
The text surveys how ReaxFF has been used for reactive processes in biochemistry: phosphodiester cleavage in RNA versus DNA (distinct mechanisms involving cyclic phosphate intermediates versus hydrolytic attack at phosphorus), Zn(II)–ligand energetics and aqueous Zn–imidazole dynamics including pH-dependent protonation, and catalyzed vs uncatalyzed peptide hydrolysis with analysis of transition-state stabilization by Cu(II). The overarching goal is to show validation against quantum data and the feasibility of large-scale reactive MD for enzymatically relevant chemistry.
Methods¶
- Scope: Book-chapter review of ReaxFF for RNA/DNA cleavage, Zn(II)-ligand and imidazole protonation, and Cu(II)-mediated peptide hydrolysis, with DFT comparisons where cited.
- QM / static ReaxFF: Potential-energy profiles along phosphodiester cleavage paths for RNA vs DNA dinucleotides (with 0, 1, or liquid water cases as plotted).
- Reactive MD example (imidazole protonation): NVT MD at 300 K in a ~20 x 20 x 20 A cell with 10 neutral imidazole, 20 HCl, and 207 H2O, replicated to a 3 x 3 x 3 supercell; Berendsen thermostat (100 fs relaxation), time step 0.1 fs, 600 ps production to track imidazolium formation at low pH.
Findings¶
- ReaxFF reproduces a specific RNA/DNA cleavage picture from the literature: RNA cleavage via a 3′,5′-cyclic phosphate intermediate giving 2′-OH,3′-phosphate and 5′-OH products; DNA cleavage by water attack at phosphorus when the 2′-OH is absent, yielding 5′-OH and nucleotide fragments.
- For Zn(II)–ligand systems, ReaxFF comparisons to prior DFT work cover dissociation energies and proton affinities across a set of N-containing ligands and imidazole; reactive MD of Zn(Im)₂(H₂O)ₙ in water illustrates variable coordination numbers from dynamic Zn(II) coordination.
- ReaxFF is argued to capture pH-dependent imidazole protonation via barrier analysis and formation of imidazolium under acidic conditions.
- For peptide hydrolysis, ReaxFF potential energy profiles along pathways for Cu(II)-catalyzed and uncatalyzed reactions show strong TS stabilization in the catalyzed case and qualitative agreement with DFT; the text highlights imidazole as a proton shuttle in Ser–His–Asp-type contexts.
Limitations¶
The corpus PDF is a publisher e-proof; final pagination, figures, and any post-proof corrections follow the published chapter. Specific numerical barriers and simulation lengths should be verified against the final book/chapter PDF.
Relevance to group¶
Direct van Duin–authored synthesis connecting ReaxFF to biomolecular reactivity and MD workflows.
Citations and evidence anchors¶
Prefer the published chapter DOI or book citation once confirmed in library metadata; the wiki stub did not record a DOI.