Sequence and structural features of enzymes and their active sites by EC class

Area of Science:

• Biochemistry
• Structural Biology
• Bioinformatics

Background:

• Enzyme classification relies on the Enzyme Commission (EC) system, but understanding the structural basis for these classifications is crucial.
• Enzyme structure-function relationships are fundamental to biochemistry and protein engineering.

Purpose of the Study:

• To systematically analyze sequence and structural differences among the six main Enzyme Commission (EC) classes.
• To elucidate how enzyme structure, particularly active site characteristics, relates to functional roles.
• To develop a predictive model for enzyme classification based on structural features.

Main Methods:

• Analysis of a non-redundant set of 294 enzymes, focusing on sequence and structural features.
• Characterization of active-site properties such as polarity and amino acid propensities.
• Clustering of correlated features and selection of representative attributes for model development.

Main Results:

• Significant differences were observed in active-site polarity, enzyme size, and amino acid propensities across EC classes.
• Oxidoreductases exhibit non-polar active sites linked to cofactor binding.
• Lyases predominantly form oligomers, while hydrolases are mostly monomers.
• A predictive model achieved 33.1% accuracy in classifying enzymes into their top EC class, a 16.4% improvement over random chance.

Conclusions:

• Enzyme structure and sequence features are distinct across major EC classes, offering insights into functional roles.
• The identified structural correlates can enhance enzyme classification and prediction of function from structure.
• This work provides a foundation for improved enzyme design and functional annotation strategies.