STRUCTURE-ACTIVITY RELATIONSHIP AND CLASSIFICATION OF ANTIMICROBIAL PEPTIDES USING SEQUENCE AND PHYSICOCHEMICAL PROPERTIES

Authors

  • Dr. Mustafa Alhaji Isa Department of Microbiology, University of Maiduguri, Maiduguri, Nigeria
  • Dr. Stephen Kayode Ojo Department of Microbiology, Federal University Oye-Ekiti, Oye-Ekiti, Nigeria
  • Dr. Tope Tunji Odunitan Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria

DOI:

https://doi.org/10.65327/bp.v12i3.2529

Keywords:

antimicrobial peptides, structure–activity relationship, physicochemical properties, machine learning, XGBoost

Abstract

Antimicrobial peptides have been regarded as potential candidates as an alternative to conventional antibiotics; however, their activity is a complex interaction between their sequence composition and physicochemical properties. This study aimed at understanding structure–activity relationships and to build machine-learning models to classify the antimicrobial peptides by combining sequence-derived and molecular descriptors. Conflicting annotations were eliminated, and amino-acid composition, hydrophobicity, hydrophobic moment, charge density, length, molecular weight, and isoelectric point and amino-acid composition were analysed for the relevant features. Antimicrobial peptides were generally shorter and more positively charged than the non-antimicrobial peptides and had a unique residue-composition pattern. Logistic regression revealed that four variables (peptide length, net charge, hydrophobic moment and aromaticity) were important independent predictors of whether a peptide was antimicrobial or not. Four classifiers were tested with sequence-only, physicochemical-only and combined feature sets. XGBoost with combined features had the highest performance with 93.6% accuracy, 0.977 ROC-AUC, 0.975 PR-AUC and 0.871 Matthews correlation coefficient. The discrimination was not so much dependent on peptide size, as evidenced by the good predictive performance of length-controlled sensitivity analysis. It is shown that these results support the usefulness of using interpretable physicochemical descriptors together with sequence data for robust prediction of antimicrobial peptides.

 

 

 

 

 

 

 

 

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Published

2026-08-28

How to Cite

Dr. Mustafa Alhaji Isa, Dr. Stephen Kayode Ojo, & Dr. Tope Tunji Odunitan. (2026). STRUCTURE-ACTIVITY RELATIONSHIP AND CLASSIFICATION OF ANTIMICROBIAL PEPTIDES USING SEQUENCE AND PHYSICOCHEMICAL PROPERTIES. International Journal For Research In Biology & Pharmacy, 12(3), 56–70. https://doi.org/10.65327/bp.v12i3.2529