ExpaRNA

ExpaRNA performs sequence-structure alignment of RNA molecules by detecting and matching exact common secondary-structure substructures to enable comparative analysis of RNA structural motifs.

Key Features:

• Exact Substructure Matching: Maintains precise alignment of common substructures across two RNA molecules, treating matched substructures as cohesive units while allowing variability between structural motifs.
• Efficient Algorithmic Performance: Computes the longest collinear sequence of substructures shared by two RNAs in O(H·n·m) time and O(n·m) space, where H is significantly smaller than n·m for real RNA structures.
• Comparison with Existing Methods: Benchmarked against RNAforester and RNA_align, achieving comparable alignment accuracy while requiring substantially less runtime.
• Integration with Sankoff-style Tools: Accelerates Sankoff-style alignment tools such as LocARNA, providing a reported speedup factor of 4.25 at the highest quality setting without compromising alignment accuracy.

Scientific Applications:

• Sequence-Structure Similarity Detection: Identifies common sequence-structure motifs between RNAs to support inference of functional roles and evolutionary relationships.
• Structural Motif Analysis: Enables rapid exploration of structural motifs that underpin specific biological functions or RNA regulatory mechanisms.

Methodology:

Detects overlapping and crossing substructure matches between two nested RNA secondary structures.