Synthesis of Zwitterionic Polymers Containing a Tertiary Sulfonium Group for Protein Stabilization

Biomacromolecules. 2019 Feb 11;20(2):904-915. doi: 10.1021/acs.biomac.8b01542. Epub 2019 Jan 24.

Abstract

The present study demonstrates the controlled synthesis and biological potential of poly( N-acryloyl-l-methionine methyl sulfonium salt)s (poly(A-Met(S+)-OH)s), which mimic dimethylsulfoniopropionate (DMSP), a compound produced by marine algae to protect their proteins. The novel sulfonium-containing zwitterionic polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of the amino acid-based monomer N-acryloyl-l-methionine (A-Met-OH) followed by a postmodification process in which the sulfide groups were reacted with iodomethane. The DMSP-mimic zwitterionic macromolecules were shown for the first time to exhibit low cytotoxicity and the ability to stabilize proteins. By adding the resulting poly(A-Met(S+)-OH)s to horse radish peroxidase (HRP) solution, the activity of HRP was maintained even after storage at 4 °C for several days. In addition, the protein activities were tested using peroxidase-labeled antibody to mouse immunoglobulin G (IgG-HRP) and alkaline phosphatase (ALP) after storage and for HRP after freeze-thaw cycles. Amphiphilic random copolymers, poly(A-Met(S+)-OH- co-BA)s, also exhibited excellent properties for protein stabilization.

MeSH terms

  • Alkaline Phosphatase / chemistry
  • Amino Acids / chemistry
  • Animals
  • Cell Line
  • Horseradish Peroxidase / chemistry
  • Hydrocarbons, Iodinated / chemistry
  • Immunoglobulin G / chemistry
  • Methionine / chemistry
  • Mice
  • Polymerization
  • Polymers / chemical synthesis*
  • Proteins / chemistry*
  • Sulfonium Compounds / chemistry*

Substances

  • Amino Acids
  • Hydrocarbons, Iodinated
  • IGG-horseradish peroxidase
  • Immunoglobulin G
  • Polymers
  • Proteins
  • Sulfonium Compounds
  • Methionine
  • dimethylpropiothetin
  • methyl iodide
  • Horseradish Peroxidase
  • Alkaline Phosphatase