Currently, antimicrobial resistance
constitutes a serious
threat
to human health. Drugs based on antimicrobial peptides (AMPs) constitute
one of the alternatives to address it. Shallow and deep learning (DL)-based
models have mainly been built from amino acid sequences to predict
AMPs. Recent advances in tertiary (3D) structure prediction have opened
new opportunities in this field. In this sense, models based on graphs
derived from predicted peptide structures have recently been proposed.
However, these models are not in correspondence with state-of-the-art
approaches to codify evolutionary information, and, in addition, they
are memory- and time-consuming because depend on multiple sequence
alignment. Herein, we presented a framework to create alignment-free
models based on graph representations generated from ESMFold-predicted
peptide structures, whose nodes are characterized with amino acid-level
evolutionary information derived from the Evolutionary Scale Modeling
(ESM-2) models. A graph attention network (GAT) was implemented to
assess the usefulness of the framework in the AMP classification.
To this end, a set comprised of 67,058 peptides was used. It was demonstrated
that the proposed methodology allowed to build GAT models with generalization
abilities consistently better than 20 state-of-the-art non-DL-based
and DL-based models. The best GAT models were developed using evolutionary
information derived from the 36- and 33-layer ESM-2 models. Similarity
studies showed that the best-built GAT models codified different chemical
spaces, and thus they were fused to significantly improve the classification.
In general, the results suggest that esm-AxP-GDL is a promissory tool
to develop good, structure-dependent, and alignment-free models that
can be successfully applied in the screening of large data sets. This
framework should not only be useful to classify AMPs but also for
modeling other peptide and protein activities.