Quantifying Molecular Flexibility Using Crystallographically Accessible Conformational Space.

Area of Science:

• Computational chemistry
• Structural bioinformatics
• Cheminformatics

Background:

• Understanding molecular flexibility is crucial for drug discovery and materials science.
• Existing methods for assessing molecular conformational space are often discrete and binary.
• The Cambridge Structural Database (CSD) contains extensive crystallographic data on small organic molecules.

Purpose of the Study:

• To introduce new informatics-based molecular descriptors for quantifying crystallographically accessible conformational space.
• To develop continuous measures of molecular rotatability based on crystal structure data.
• To provide ensemble scores that account for molecular topology and define bounds for accessible configuration space.

Main Methods:

• Utilized small organic molecule crystal structures from the Cambridge Structural Database (CSD).
• Developed novel informatics-based descriptors to numerically measure conformational space, considering rotamers and rings.
• Introduced two ensemble combinations of rotatability scores to adjust for molecular topology.

Main Results:

• Introduced continuous measures of covalent bond rotatability, moving beyond discrete classifications.
• Developed ensemble scores providing quantitative upper and lower bounds for accessible molecular configuration space in crystal structures.
• Demonstrated a novel approach to assess molecular flexibility using crystallographic data.

Conclusions:

• The new descriptors offer a quantitative assessment of molecular flexibility in the context of crystal structures.
• These methods provide a more nuanced understanding of accessible molecular configuration space compared to traditional binary classifications.
• The developed ensemble scores are valuable for analyzing molecular flexibility and conformational dynamics.