On the relationship between residue structural environment and sequence conservation in proteins

Area of Science:

• Structural biology
• Bioinformatics
• Evolutionary biology

Background:

• Evolutionary conservation of residues is key to protein function and structure.
• Sequence conservation analysis typically requires extensive homologous sequences.
• Previous work linked sequence conservation to weighted contact number (WCN) using Cα positions.

Purpose of the Study:

• To determine if Cα atomic positions are sufficient for analyzing residue environment and sequence conservation.
• To compare the contribution of Cα atoms versus other protein substructures in predicting sequence conservation.

Main Methods:

• Calculated weighted contact number (WCN) and other environmental measures using Cα positions.
• Compared WCN and environmental measures derived from Cα atoms with those from all-atom, backbone, and side-chain substructures.
• Quantified the overlapping contributions of different substructures to sequence conservation.

Main Results:

• Cα atomic positions are largely equivalent to other substructures (all-atom, backbone, side-chain) in calculating residue environment measures.
• High overlapping contributions (e.g., 87% for WCN between Cα and all-atom) were observed.
• The structure-conservation relationship remains similar regardless of the substructure used.

Conclusions:

• Cα atomic positions alone are adequate for reflecting sequence conservation at the residue level.
• This simplifies the identification of evolutionarily important residues.
• Future studies can leverage Cα-based analysis for efficient protein function and structure prediction.