title: Quantitative analysis of the thermal stability of the gamma phage endolysin PlyG: a biophysical and kinetic approach to assaying therapeutic potential.
abstract: Endolysins are lytic enzymes encoded by bacteriophage that represent an emerging class of protein therapeutics. Considering macromolecular thermoresistance correlates with shelf life, PlyG, a Bacillus anthracis endolysin, was thermally characterized to further evaluate its therapeutic potential. Results from a biophysical thermal analysis revealed full-length PlyG and its isolated domains comprised thermal denaturation temperatures exceeding 63°C. In the absence of reducing agent, PlyG was determined to be kinetically unstable, a finding hypothesized to be attributable to the chemical oxidation of cysteine and/or methionine residues. The presence of reducing agent kinetically stabilized the endolysin, with PlyG retaining at least ~50% residual lytic activity after being heated at temperatures up to 80°C and remaining enzymatically functional after being boiled. Furthermore, the endolysin had a kinetic half-life at 50°C and 55°C of 35 and 5.5h, respectively. PlyG represents a thermostable proteinaceous antibacterial with subsequent prolonged therapeutic shelf life expectancy.
authors.affiliation: Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Heselpoth
authors.affiliation: Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Biotechnology Program, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Owens
authors.affiliation: Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA. Electronic address: nelsond@umd.edu.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Nelson
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000528:radiation effects; D001408:Bacillus anthracis / Q000201:enzymology*; D004795:Enzyme Stability; D007700:Kinetics; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry* / Q000528:radiation effects*; D011489:Protein Denaturation / Q000528:radiation effects; D055550:Protein Stability; D013696:Temperature; D014764:Viral Proteins / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D000900:Anti-Bacterial Agents; D014764:Viral Proteins; C465450:PlyG lysin, gamma phage; D009238:N-Acetylmuramoyl-L-alanine Amidase
keywords: Anthrax; Antimicrobial; Bacteriophage; Endolysin; PlyG; Thermal stability