pqsfinder

pqsfinder identifies potential quadruplex-forming sequences (PQS) in DNA, detecting motifs that may fold into intramolecular G-quadruplexes (G4) formed by guanine-rich tracts and stabilized by monovalent cations (commonly K+), to support analysis of G4-related genomic functions.

Key Features:

• Advanced detection capabilities: Identifies candidate G4-forming sequences including imperfect G-runs containing bulges or mismatches, enabling detection of a broader spectrum of G4-like motifs than many heuristic pattern matchers.
• Customizable and flexible searches: Search parameters can be tuned to accommodate deviations from canonical G4 motif composition and spacing, supporting exploration of structurally heterogeneous PQS candidates.
• High-precision scoring model: Includes a scoring framework parameterized via training to improve discrimination of plausible PQS, reporting ~96% accuracy on a benchmark of 392 experimentally observed G4 structures.
• Correlation with experimental data: Predictions show agreement with experimental profiling (e.g., G4-seq), including a reported correlation coefficient of 0.622 compared with 0.491 for G4Hunter on the same comparison.
• Optimized algorithm for efficiency: Employs a recursive search strategy optimized to reduce evaluation of suboptimal PQS conformations, improving runtime efficiency.

Scientific Applications:

• Genomic PQS screening: Enables systematic screening of DNA sequences for putative G4 formation sites in genomic analyses.
• Regulatory and functional annotation: Facilitates studies of regulatory enrichment and functional annotation associated with G4 structures.
• Mechanistic studies: Supports hypothesis generation regarding roles of G4 structures in replication, transcription, genome stability, and related molecular processes.
• Research and biotechnology workflows: Sensitivity to imperfect motifs makes it applicable to both foundational research and applied biotechnology workflows.

Methodology:

Detection of candidate G4s including imperfect G-runs with bulges or mismatches; recursive search strategy to prune evaluation of suboptimal PQS conformations; scoring framework parameterized via training; comparisons made to experimental profiling such as G4-seq.