title: Investigation on the reaction conditions of Staphylococcus aureus sortase A for creating surface-modified liposomes as a drug-delivery system tool.
abstract: OBJECTIVE
  This study aimed to determine the preferred conditions for the transpeptidase reaction of sortase A from Staphylococcus aureus, for the purpose of creating functional liposomes useful for a drug-delivery system (DDS).
  
  
  METHODS
  His-tagged recombinant sortase A with 59 amino acids deleted from the N-terminus (His-ΔN59SrtA) was prepared using an Escherichia coli expression system. The pH dependency and sorting signal sequence dependency of the transpeptidase reaction of His-ΔN59SrtA were analyzed by monitoring the transfer of model donor-substrates (i.e. His-tagged mutant green fluorescent proteins with a C-terminal LPxTG sorting signal) to model acceptor-beads with a GGGGGC peptide. In addition, using preferred conditions, the sortase A reaction was used to modify liposome surface.
  
  
  CONCLUSIONS
  The transpeptidase reaction of His-ΔN59SrtA was enhanced under weakly acidic conditions. Transfer efficiency, based on sorting signal recognition by His-ΔN59SrtA, was similar to or higher than that obtained using several substrates with amino acids other than Glu in the sorting signal position "x". Furthermore, liposomes containing GGGGGC peptide-linked dipalmitoylphosphatidylethanolamine were successfully modified using the preferred conditions for His-ΔN59SrtA determined in this study.
  
  
  CONCLUSIONS
  Preferred conditions for the transpeptidase reaction of His-ΔN59SrtA, especially in a weakly acidic environment to enhance reaction, was established and successfully used to create functional liposomes applicable to DDS.
authors: Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima, Japan.
authors: Atsushi
authors: A
authors: Tabata
authors: Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima, Japan.
authors: Natsuki
authors: N
authors: Anyoji
authors: Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima, Japan.
authors: Yukimasa
authors: Y
authors: Ohkubo
authors: Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima, Japan.
authors: Toshifumi
authors: T
authors: Tomoyasu
authors: Department of Biological Science and Technology, Life System, Institute of Technology and Science, The University of Tokushima Graduate School, Tokushima, Japan nagamune@bio.tokushima-u.ac.jp.
authors: Hideaki
authors: H
authors: Nagamune
mesh_terms: D019881:Aminoacyltransferases / Q000008:administration & dosage*; D001426:Bacterial Proteins / Q000008:administration & dosage*; D003546:Cysteine Endopeptidases / Q000008:administration & dosage*; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D013211:Staphylococcus aureus / Q000201:enzymology*; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D008081:Liposomes; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases
keywords: Sortase A; Staphylococcus aureus; drug-delivery system; liposome