,
Tetsuo Shibuya
Creative Commons Attribution 4.0 International license
Identifying shared substructures in 3D protein models is essential for structural bioinformatics. This task can be modeled as a sequential Largest Common Point-set (LCP) problem under the bottleneck distance. We propose a new O(n^13 log n)-time exact algorithm for this problem, which improves upon the previous best-known complexity of O(n^14), where n is the maximum size of the two input structures. Since these theoretical bounds are practically too large, an O(n⁷ log n)-time approximation algorithm with solution-size guarantees has been proposed; however, it remains too time-consuming for practical applications. Thus, we also propose a new filtering technique to enhance the approximation algorithm without increasing the theoretical time complexity or losing the solution-size guarantees. Experiments with PDB data show that our technique achieves over a 24-fold speedup at n = 130. While the previous algorithm required 3.80 hours on average for n = 130 in our experiments, making it difficult to test larger structures, our algorithm can process n = 200 in only 2.33 hours on average.
@InProceedings{tsukahara_et_al:LIPIcs.WABI.2026.7,
author = {Tsukahara, Masahito and Shibuya, Tetsuo},
title = {{Theoretically and Practically Faster Algorithms for Protein Structure Alignment}},
booktitle = {26th International Conference on Algorithms for Bioinformatics (WABI 2026)},
pages = {7:1--7:13},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-446-8},
ISSN = {1868-8969},
year = {2026},
volume = {390},
editor = {El-Mabrouk, Nadia and Vandin, Fabio},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.WABI.2026.7},
URN = {urn:nbn:de:0030-drops-275116},
doi = {10.4230/LIPIcs.WABI.2026.7},
annote = {Keywords: Structural Bioinformatics, Pairwise Alignment, Exact Algorithm, Approximation Algorithm, Computational Geometry}
}
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