Identification of protegrin-1 as a stable and nontoxic scaffold among protegrin family – a computational approach

Achieving both, nontoxicity and stability in antimicrobial peptides (AMP) is a challenge. This study predicts a structurally stable, nontoxic scaffold among the protegrin family, for future therapeutic peptide analogs. Protegrins (PG) are a class of pharmaceutically approved, in demand AMPs, which require further improvement in terms of nontoxicity and stability. Out of five protegrins viz., PG1, PG2, PG3, PG4 and PG5, PG1 has been predicted as best scaffold. Prediction was based upon sequential elimination of other protegrins, using computational methods to assess the extracellular bacterial membrane penetrability, nontoxicity and structural stability by geometric observables. Initially, PG2 and PG4 showing the lowest membrane penetrability and highest toxicity respectively, were screened out. Among the remaining three protegrins, PG1 displayed both lowest root mean square deviation and radius of gyration, with a considerable occupancy of seven H-bonds and established uniform secondary structure profile throughout its ensembles. Therefore, the authors claim the superiority of PG1 as a nontoxic stable scaffold among its family.
Communicated by Ramaswamy H. Sarma