PIMMS is a high performance lattice-based 2D/3D Monte Carlo simulation engine. It can be used to explore how polymer sequence architecture impacts phase transitions, but more generally can be used to explore the sequence specific behaviour of disordered polymers such as intrinsically disordered proteins. It facilitates full phase space exploration as well as arbitrary sequence complexity and residue-residue parameterization.
PIMMS is currently under development by Alex Holehouse in the Pappu lab at Washington University in St. Louis.
For any questions please contact alex at email@example.com
Extensive new results from PIMMS were presented at an invited talk in the Biopolymers in vivo subgroup meeting at the 2018 Biophysical Society Meeting in San Francisco. Thanks to Dora and Allan for the invitation to speak.
A set of new methods for estimating intra-droplet concentration have been implemented. These methods provide a robust method to estimate full phase diagrams.
PIMMS simulations have been able to quantitativly and rapidly reproduce a range of phenomena previously observed in both all-atom and coarse grained simulation engines. We're gearing up to write the PIMMS paper!
New analysis and move-types have been added for enhanced performance. This has provided a significant inprovement for dense systems. Analysis from PIMMS was also used in our recent JACS paper  (see the SI).
A full re-write of the inner-loops has brought the average simulation speed to ~3 billion steps per day. There's plenty of room for further performance improvement!
PIMMS is being debuted publicly at the 2016 Biophysical Society meeting in Los Angeles on Sunday February 28th in the IDPs and Aggregates session. I (Alex) will be giving a talk on an early result relating to the role of charge patterning on polyelectrolyte complex coacervation.
PIMMS now has fully functional long range electrostatics implemented as interaction energies which extend over multiple lattice sites. Early results are extremely promising!
 E.W. Martin*, A.S. Holehouse*, C.R. Grace, A. Hughs, R.V. Pappu✝, T. Mittag✝ [*Co-first authors, ✝Co-corresponding authors] (2016) Sequence Determinants of the Conformational Properties of an Intrinsically Disordered Protein Prior to and Upon Multisite Phosphorylation. Journal of the American Chemical Society, 138: 15323-15335.