Figures
Fig. 3 States of acrylonitrile. (A) Azotosome. Interlocking nitrogen and hydrogen atoms reinforce the structure. (B) Solid. Adjacent nitrogen atoms create some unfavorable repulsion. (C) Micelle. Adjacent nitrogen atoms make this highly unfavorable. (D) Azotosome vesicle of diameter 90 Å, the size of a small virus particle.
Tables
- Table 2 Error in OPLS-optimized structures.
Average difference, for each species, between its OPLS structure and the structure obtained via ab initio optimization with Onsager’s self-consistent reaction field (SCRF) model of an implicit solvent.
Species Δ(bond
length) (Å)Δ(bond
angle) (°)Δ(dihedral)
(°)Propanenitrile 0.00 0.5 0.0 Butanenitrile 0.01 0.5 0.1 Pentanenitrile 0.01 0.4 0.1 Hexanenitrile 0.00 0.6 0.2 Aminopropane 0.01 0.7 0.7 Aminobutane 0.01 0.6 0.6 Aminopentane 0.01 0.6 0.4 Aminohexane 0.01 0.5 0.2 Hexane 0.01 0.3 0.0 Methane 0.02 1.5 0.0 HCN 0.01 0.0 0.0 Acrylonitrile 0.01 1.2 0.0 Acetonitrile 0.00 0.0 0.0 Cyanoacetylene 0.05 6.3 0.0 Cyanoallene 0.08 9.5 0.0 2,4-Pentadiynenitrile 0.06 75.8 0.0 - Table 3 Pairwise binding energies.
OPLS and ab initio calculations produced similar results.
Species OPLS
(kcal/mol)DFTvacuum
(kcal/mol)DFTsolvent
(kcal/mol)Propanenitrile −6.4 −7.5 −6.2 Methane 0.0 0.0 0.0 HCN −4.1 −3.0 −2.3 Acrylonitrile −5.6 −6.0 −4.9 Acetonitrile −5.9 −6.3 −5.0 - Table 4 Flexibility Ka of nitrile and amine azotosomes, and activation energy ΔE to remove a molecule from each azotosome.
Species Ka (J/m2) ΔE (kcal/mol) Acrylonitrile 0.26 17.1 Acetonitrile 0.37 5.8 Propanenitrile 0.10 7.6 Butanenitrile 0.13 6.4 Pentanenitrile 0.55 8.4 Hexanenitrile 0.26 6.0 Aminopropane 0.22 5.2 Aminobutane 0.19 6.7 Aminopentane 0.28 7.7 Aminohexane 0.30 7.7 Hexane bilayer 2.20 — - Table 5 Gibbs free energy of decomposition.
The net mechanical work required to remove a molecule from the membrane, within 20% uncertainty. These values are concentration-dependent.
Species ΔG (kcal/mol) Acrylonitrile 7.6 Acetonitrile 17.4 Propanenitrile 6.4 Butanenitrile 7.1 Pentanenitrile 13.4 Hexanenitrile 11.5 Aminopropane 5.9 Aminobutane 6.7 Aminopentane 9.6 Aminohexane 6.2
