Sortase-Mediated Surface Functionalization of Stimuli-Responsive Microgels

Biomacromolecules. 2017 Sep 11;18(9):2789-2798. doi: 10.1021/acs.biomac.7b00720. Epub 2017 Aug 4.

Abstract

In this work we explored an enzyme-mediated method for selective and efficient decoration of aqueous microgels with biomolecules. Poly(N-vinylcaprolactam) (VCL) microgels with varied amounts of glycidyl methacrylate (GMA) as comonomer incorporated in the microgel shell were synthesized and characterized in regard to their size, swelling degree, and temperature-responsiveness in aqueous solutions. The surface of the PVCL/GMA microgel containing 5 mol % glycidyl methyacrylate was modified by grafting of a specific recognition peptide sequence (LPETG) for Sortase A from Staphylococcus aureus (Sa-SrtAΔ59). Sortase-mediated conjugation of the enhanced Green Fluorescent Protein (eGFP) carrying a N-terminal triglycine tag to LPETG-modified microgels was successfully performed. Conjugation of eGFP to the microgel surface was qualitatively proven by confocal microscopy and by fluorescence intensity measurements. The developed protocol enables a precise control of the amount of eGFP grafted to the microgel surface as evidenced by the linear increase of fluorescence intensity of modified microgel samples. The kinetic of the sortase-mediated coupling reaction was determined by time-dependent fluorescence intensity measurements. In summary, sortase-mediated coupling reactions are a simple and powerful technique for targeted surface functionalization of stimuli-responsive microgels with biomolecules.

MeSH terms

  • Aminoacyltransferases / chemistry
  • Aminoacyltransferases / metabolism*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Caprolactam / analogs & derivatives*
  • Caprolactam / chemistry
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / metabolism*
  • Green Fluorescent Proteins / chemistry
  • Hydrogels / chemical synthesis*
  • Hydrogels / chemistry
  • Methacrylates / chemistry
  • Peptide Fragments / chemistry
  • Polymers / chemistry*
  • Staphylococcus aureus / enzymology

Substances

  • Bacterial Proteins
  • Hydrogels
  • Methacrylates
  • Peptide Fragments
  • Polymers
  • Green Fluorescent Proteins
  • poly-N-vinylcaprolactam
  • Caprolactam
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases