DAS

DAS predicts transmembrane segments in integral membrane proteins by using low-stringency dot-plots to compare a query sequence against a curated collection of non-homologous membrane proteins with a previously derived scoring matrix.

Key Features:

• Single-sequence operation: Predicts transmembrane regions using only the query sequence without requiring multiple sequence alignments.
• Low-stringency dot-plots: Employs low-stringency dot-plot comparisons between the query and reference membrane proteins.
• Curated non-homologous reference set: Compares the query sequence against a curated collection of non-homologous membrane proteins.
• Derived scoring matrix: Utilizes a previously derived scoring matrix to evaluate alignments in the dot-plots.
• Applicability beyond positive-inside rule: Can predict transmembrane segments in proteins that do not conform to the positive-inside rule.
• Comparable performance: Performs comparably to earlier methods that require additional data such as multiple sequence alignments or distributions of positively charged residues.

Scientific Applications:

• Transmembrane segment prediction: Identification of transmembrane helices and segment boundaries in integral membrane proteins.
• Membrane protein topology analysis: Characterization of membrane protein topology for studies of structure and function.
• Structural biology: Support for interpreting membrane protein structure and interactions within cellular membranes.
• Drug discovery: Informing target validation and lead optimization through accurate prediction of membrane protein topology.

Methodology:

Low-stringency dot-plots compare the query sequence to a curated set of non-homologous membrane proteins using a previously derived scoring matrix to identify transmembrane segments.