The twilight zone of cis element alignments.

Area of Science:

• Bioinformatics
• Computational Biology
• Molecular Biology

Background:

• Sequence alignment is crucial in bioinformatics, but aligning short DNA sequences and motifs presents challenges.
• Existing tools often struggle with the nuances of regulatory element comparison.

Purpose of the Study:

• To evaluate TFcompare, a structural alignment method for protein-DNA complexes.
• To benchmark pairwise alignment of regulatory elements and define alignment confidence limits.
• To assess the relevance of these thresholds using experimentally derived elements.

Main Methods:

• Structural superposition of transcription factors and sequence alignment of their recognized cis elements.
• Benchmarking pairwise alignment of regulatory elements using TFcompare.
• Defining and evaluating confidence limits and twilight zones for sequence alignments.

Main Results:

• The structure of cis elements and protein-DNA interfaces is significantly more conserved than their sequence.
• Structural conservation impacts alignment accuracy when relying solely on sequence information.
• DNA motifs represented as matrices yield superior alignment outcomes compared to individual sequences.

Conclusions:

• Structural alignment methods offer improved accuracy for cis-element comparison.
• Empirical and theoretical twilight thresholds aid in assessing regulatory sequence plasticity.
• These thresholds are valuable for filtering unreliable sequence alignments.