Conspectus
Pivotal to the success of any
computational experiment is the ability
to make reliable predictions about the system under study and the
time required to yield these results. Biomolecular interactions is
one area of research that sits in every camp of resolution vs the
time required, from the quantum mechanical level to in vivo studies. At an approximate midpoint, there is coarse-grained molecular
dynamics, for which the Martini force fields have become the most
widely used, fast enough to simulate the entire membrane of a mitochondrion
though lacking atom-specific precision. While many force fields have
been parametrized to account for a specific system under study, the
Martini force field has aimed at casting a wider net with more generalized
bead types that have demonstrated suitability for broad use and reuse
in applications from protein–graphene oxide coassembly to polysaccharides
interactions.
In this Account, the progressive (Martini versions
1 through 3)
and peripheral (Sour Martini, constant pH, Martini Straight, Dry Martini,
etc.) developmental trajectory of the Martini force field will be
analyzed in terms of self-assembling systems with a focus on short
(two to three amino acids) peptide self-assembly in aqueous environments.
In particular, this will focus on the effects of the Martini solvent
model and compare how changes in bead definitions and mapping have
effects on different systems. Considerable effort in the development
of Martini has been expended to reduce the “stickiness”
of amino acids to better simulate proteins in bilayers. We have included
in this Account a short study of dipeptide self-assembly in water,
using all mainstream Martini force fields, to examine their ability
to reproduce this behavior. The three most recently released versions
of Martini and variations in their solvents are used to simulate in
triplicate all 400 dipeptides of the 20 gene-encoded amino acids.
The ability of the force fields to model the self-assembly of the
dipeptides in aqueoues environments is determined by the measurement
of the aggregation propensity, and additional descriptors are used
to gain further insight into the dipeptide aggregates.