About PairMap2
PairMap2 is a tool for improving the accuracy of relative binding free energy perturbation (RBFEP) calculations
by introducing intermediate molecules between structurally distant compound pairs.
Large topological transformations — such as scaffold hops or ring insertions/deletions — are decomposed into
smaller, more tractable perturbation steps via automatically generated intermediates.
Pair Mode
Given two input molecules (source and target), finds intermediate compounds and constructs a perturbation map
connecting source → intermediates → target, with thermodynamic cycles for reliability.
Map Mode
Given a set of molecules (e.g., a congeneric series), constructs an optimized perturbation map covering all
input compounds, automatically resolving difficult edges by introducing intermediates.
Job history is retained for 90 days. After that, jobs and their results are automatically deleted.
Disclaimer
This service is provided for evaluation purposes only. For continued or production use, please use the local version.
Data and environments will be deleted 90 days after job submission and may be deleted or updated without prior notice.
We do not guarantee any technical support or maintenance for this service. We assume no liability for any damages arising from or related to the use of this service.
Development
Developed by Kairi Furui, Takafumi Shimizu, Yutaka Akiyama, S. Roy Kimura, Yoh Terada, and Masahito Ohue
(Institute of Science Tokyo / Ohue Lab).
Tutorial
Pair Mode
- Enter SMILES for the Source and Target molecules, or switch to SDF mode and upload SDF files.
-
Optionally adjust parameters:
- Search Parameters — control intermediate generation (atom modification, ring capping, MCS seed, etc.).
- Map Generation — control path length, rough/min score thresholds, and optimal path mode.
- Click Generate. PairMap2 will exhaustively generate intermediates, find the optimal path, and build the perturbation map.
- In the result graph, click a node to inspect the 3D structure; click an edge to see the MCS-highlighted structural difference between the two endpoint molecules.
- Download the results: Map SDF (molecules on the map), Links CSV (edges with scores), or All Intermediates SDF.
Map Mode
- Upload a multi-molecule SDF file containing your compound series, or click Example to load the p38 example set.
- Review the molecule list. You can also add individual molecules by SMILES or remove entries.
- Optionally adjust Map Parameters (similarity threshold, max degree, max path length, etc.).
- Click Submit Job. The job will be queued and processed on the server.
- Monitor progress in the Jobs table (use Refresh or wait for auto-update). When the status is completed, click View.
- In the result graph, click an edge to view the MCS difference (common / deleted / inserted atoms highlighted) between the two connected molecules.
- Download: Intermediates SDF, Links CSV, or Map JSON.
Citation
If you use PairMap2 in your research, please cite the PairMap method:
Furui, K.; Shimizu, T.; Akiyama, Y.; Kimura, S. R.; Terada, Y.; Ohue, M.
PairMap: An Intermediate Insertion Approach for Improving the Accuracy of Relative Free Energy Perturbation Calculations for Distant Compound Transformations.
J. Chem. Inf. Model. 2025,
65 (2), 705–721.
DOI:
10.1021/acs.jcim.4c01634
@article{Furui2025-uy,
author = {Furui, Kairi and Shimizu, Takafumi and Akiyama, Yutaka and
Kimura, S Roy and Terada, Yoh and Ohue, Masahito},
title = {{PairMap: An intermediate insertion approach for improving the
accuracy of relative free energy perturbation calculations for
distant compound transformations}},
journal = {J. Chem. Inf. Model.},
publisher = {American Chemical Society},
volume = {65},
number = {2},
pages = {705--721},
month = jan,
year = {2025},
url = {https://pubs.acs.org/doi/full/10.1021/acs.jcim.4c01634},
doi = {10.1021/acs.jcim.4c01634},
}