QuasiMotiFinder

QuasiMotiFinder identifies signature-like sequence patterns by combining physicochemical similarity and evolutionary conservation to improve protein function prediction against PROSITE signatures.

Key Features:

• Physicochemical Similarity: Uses a permissive search strategy to identify sequence patterns that are physicochemically similar to PROSITE motifs rather than requiring exact matches.
• Evolutionary Conservation: Calculates sequence profiles from multiple sequence alignments (MSAs) of homologous proteins and incorporates conservation information to reduce false positive predictions.
• Complementary to Profile Searches: Searches an MSA of homologous query proteins against original PROSITE signatures to complement simple pattern searches and profile-based approaches, reducing false negative and false positive rates.

Scientific Applications:

• Protein annotation: Improves identification of functional motifs in protein sequences for more accurate annotation.
• Evolutionary analysis: Supports elucidation of evolutionary relationships among proteins through detection of conserved signature-like patterns.
• Target identification: Assists in identifying potential targets for drug discovery and genetic engineering by detecting functional signatures missed by exact-match searches.

Methodology:

Calculates sequence profiles from MSAs of homologous proteins sharing the same function and uses those profiles to search against PROSITE signatures, while also detecting signature-like patterns based on physicochemical similarity rather than strict sequence identity.