SAS WS

SAS WS integrates structural information with protein sequence analysis to annotate residues based on structural context and to identify distant homologues through structure-based comparisons.

Key Features:

• Structural Annotation: Generates Sequence Annotated by Structure (SAS) files that map structural information onto protein sequences for residue-level functional annotation.
• Structure-based alignment/search: Aligns query protein sequences against sequences with known 3D structures to detect distant homologues.
• Residue Coloring: Colors residues according to secondary structure, interatomic contacts, and active site information to highlight structural and functional sites.
• Structure Inspection: Examines specific properties of individual protein structures to provide detailed structural characteristics.

Scientific Applications:

• Identification of Distant Homologues: Detects distant homologous sequences by leveraging structural similarity beyond sequence identity.
• Functional Residue Annotation: Provides context-specific functional annotation of residues using structural context and annotations from resources such as the Catalytic Site Atlas and PDBsum.
• Structural Analysis and Comparison: Enables comparison of protein structures to identify conserved features and explore structure–function relationships.

Methodology:

Scans protein sequences against known 3D structures in the Protein Data Bank (PDB) and uses structural information from the Catalytic Site Atlas and PDBsum to annotate sequences with functional insights.