Generalized Approach towards Secretion-Based Protein Production via Neutralization of Secretion-Preventing Cationic Substrate Residues

Abstract

Many heterologous proteins can be secreted by bacterial ATP-binding cassette (ABC) transporters, provided that they are fused with the C-terminal signal sequence, but some proteins are not secretable even though they carry the right signal sequence. The invention of a method to secrete these non-secretable proteins would be valuable both for understanding the secretory physiology of ABC transporters and for industrial applications. Herein, we postulate that cationic “supercharged” regions within the target substrate protein block the secretion by ABC transporters. We also suggest that the secretion of such substrate proteins can be rescued by neutralizing those cationic supercharged regions via structure-preserving point mutageneses. Surface-protruding, non-structural cationic amino acids within the cationic supercharged regions were replaced by anionic or neutral hydrophilic amino acids, reducing the cationic charge density. The examples of rescued secretions we provide include the spike protein of SARS-CoV-2, glutathione-S-transferase, streptavidin, lipase, tyrosinase, cutinase, growth factors, etc. In summary, our study provides a method to predict the secretability and a tool to rescue the secretion by correcting the secretion-blocking regions, making a significant step in understanding the physiological properties of ABC transporter-dependent protein secretion and laying the foundation for the development of a secretion-based protein-producing platform.

The potential use of bacteria and bacterial derivatives as drug delivery systems for viral infection

“…The present study represents a noteworthy contribution to our comprehension of the physiological attributes of protein secretion that rely on ABC transporters. Furthermore, it establishes a foundation for developing a protein-producing platform based on secretion by providing a means to anticipate secretability and a mechanism to restore secretion by eliminating regions that impede it [ 43 ].…”

Overcoming Biological Barriers: Importance of Membrane Transporters in Homeostasis, Disease and Disease Treatment

“…The paper “Generalized Approach towards Secretion-Based Protein Production via Neutralization of Secretion-Preventing Cationic Substrate Residues” by Byun at al. [ 9 ] is another study on bacterial transporters. Bacterial ATP-binding cassette (ABC) transporters are able to secrete heterologous proteins.…”