PASylation Enhances the Stability, Potency, and Plasma Half‐Life of Interferon α‐2a: A Molecular Dynamics Simulation

Abstract

In this study, the effectiveness of PASylation in enhancing the potency and plasma half‐life of pharmaceutical proteins has been accredited as an alternative technique to the conventional methods such as PEGylation. Proline, alanine, and serine (PAS) chain has shown some advantages including biodegradability improvement and plasma half‐life enhancement while lacking immunogenicity or toxicity. Although some experimental studies have been performed to find the mechanism behind PASylation, the detailed mechanism of PAS effects on the pharmaceutical proteins has remained obscure, especially at the molecular level. In this study, the interaction of interferon α‐2a (IFN) and PAS chain is investigated using molecular dynamics simulation method. Several important parameters including secondary structure, root‐mean‐square distance, and solvent accessible surface area to investigate the stability, bioavailability, and bioactivity of the PASylated protein are studied. The results demonstrate that IFN conformation is not affected critically through PASylation while it results in improvement of the protein stability and bioactivity. Therefore, PASylation can be considered as a proper biological alternative technique to increase the plasma half‐life of the biopharmaceutical proteins through enlarging apparent volume. The proposed simulation represents a computational approach that would provide a basis for the study of PASylated pharmaceutical proteins for different future applications.

Molecular Dynamics Simulations for Rationalizing Polymer Bioconjugation Strategies: Challenges, Recent Developments, and Future Opportunities

“…Further modeling work on PEGylation and PASylation of interferons, as well as conjugation of (EK) 10 to ubiquitin, GLP-1 and insulin represent case studies where MD simulations are used to predict and compare the impact of different polymer architectures in a protein-dependent way. By analysis of ratios of R g values and hydrophilic/hydrophobic SASA, for example, bioavailability and solubility can be assessed.…”

“…A comparable study on IFN-α2a investigated PASylation (proline, alanine and serine) as alternative to PEGylation. 155 Long, unstructured peptide chains composed of these amino acids can provide similar advantages as PEG, but overcome some of its limitations, e.g., via biodegradation. IFN-PAS x conjugates (x = 100, 200, 400, 600) were simulated for 125 ns each using the CHARMM36m force field.…”

Current Use of Asparaginase in Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma

“…Alternative strategies are being explored including a method termed PASylation in which the therapeutic protein is fused with a conformationally disordered 600 residue polypeptide rich in proline/alanine +/- serine ( 120 ). PASylation has been used to extend the half-life of a number of compounds ( 121 ) including immunostimulatory peptides ( 122 ), interferons ( 123 ), and urate oxidase ( 124 ). A PASylated Erwinia asparaginase is currently in the pre-clinical pipeline for Jazz pharmaceuticals 3 , offering hope for a long-acting Erwinia asparaginase in the future.…”

Forms and Methods for Interferon’s Encapsulation

“…Other forms of gene fusion conjugation have been evaluated as an alternative to PEGylation: PASylation and binding to human serum albumin (HSA) to increase the half-life of IFNs [ 80 ]. In the case of PASylation of IFN-α and IFN-β, a terminal polypeptide sequence rich in proline, alanine, and serine (PAS) was added [ 81 ], which increased stability, bioavailability, and biological activity, with minimal toxicity and immunogenicity [ 82 , 83 , 84 ] but did not reach the clinical phase [ 85 ]. Through the fusion of IFN-α-2b with HSA, the FDA-approved formulation Albuferon ® (Human Genome Sciences Inc., Rockville, Maryland, U.S. in collaboration with Novartis AG) was developed, which improved pharmacokinetics by increasing the half-life and maintaining its stabilization.…”