A comparative molecular field analysis study on several bioactive peptides using the alignment rules derived from...

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Structural Biology

Background:

• Aligning flexible molecules is crucial for drug discovery and understanding biological activity.
• Existing alignment methods may not optimally represent the conformational space of flexible peptides.

Purpose of the Study:

• To evaluate a novel 3D convex hull computation algorithm for aligning flexible peptide structures.
• To compare the effectiveness of convex hull alignment with traditional C-alpha atom alignment using Comparative Molecular Field Analysis (CoMFA).

Main Methods:

• Generated 1000 random structures for eleven bioactive tachykinin peptides.
• Applied a 3D convex hull algorithm to identify commonly exposed atoms for structural alignment.
• Utilized SYBYL 6.4 software for alignment via FIT option and performed Comparative Molecular Field Analysis (CoMFA).
• Compared alignment results using convex hull-derived correspondences versus C-alpha atom coordinates.

Main Results:

• Convex hull alignment revealed a lower degree of structural similarity compared to C-alpha alignment.
• Despite lower similarity, convex hull alignment yielded superior Comparative Molecular Field Analysis (CoMFA) statistics.
• These findings were consistent across different atom types and subsets of structures.

Conclusions:

• 3D convex hull computation is a feasible and effective method for aligning highly flexible molecular structures.
• This novel alignment strategy enhances the predictive power of Quantitative Structure-Activity Relationship (QSAR) models like CoMFA.
• The approach offers a promising alternative for molecular modeling and virtual screening of flexible ligands.