title: PEG and mPEG-anthracene conjugate with trypsin and trypsin inhibitor: hydrophobic and hydrophilic contacts.
abstract: The conjugation of trypsin (try) and trypsin inhibitor (tryi) with poly(ethylene glycol) (PEG) and methoxypoly(ethylene glycol) anthracene (mPEG-anthracene) was investigated in aqueous solution, using multiple spectroscopic methods, thermodynamic analysis, and molecular modeling. Thermodynamic parameters ΔS, ΔH, and ΔG showed protein-PEG bindings occur via H-bonding and van der Waals contacts with trypsin inhibitor forming more stable conjugate than trypsin. As polymer size increased more stable PEG-protein conjugate formed, while hydrophobic mPEG-anthracene forms less stable protein complexes. Modeling showed the presence of several H-bonding contacts between polymer and amino acids that stabilize protein-polymer conjugation. Polymer complexation induces more perturbations of trypsin inhibitor structure than trypsin with reduction of protein alpha-helix and major increase in random structures, indicating protein structural destabilization.
authors.affiliation: a Department of Chemistry-Biochemistry and Physics , University of Québec at Trois-Rivières , C. P. 500, Trois-Rivieres G9A 5H7 , Quebec , Canada.
authors.forename: P
authors.initials: P
authors.lastname: Chanphai
authors.affiliation: a Department of Chemistry-Biochemistry and Physics , University of Québec at Trois-Rivières , C. P. 500, Trois-Rivieres G9A 5H7 , Quebec , Canada.
authors.forename: D
authors.initials: D
authors.lastname: Agudelo
authors.affiliation: a Department of Chemistry-Biochemistry and Physics , University of Québec at Trois-Rivières , C. P. 500, Trois-Rivieres G9A 5H7 , Quebec , Canada.
authors.forename: H A
authors.initials: HA
authors.lastname: Tajmir-Riahi
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000737:chemistry*; D001665:Binding Sites; D002417:Cattle; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D010179:Pancreas / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D054730:Protein Interaction Domains and Motifs; D012996:Solutions; D013025:Glycine max / Q000737:chemistry; D013816:Thermodynamics; D014357:Trypsin / Q000737:chemistry* / Q000302:isolation & purification; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D014867:Water / Q000737:chemistry*
chemical_list: D000873:Anthracenes; D012996:Solutions; D014361:Trypsin Inhibitors; D014867:Water; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol; D014357:Trypsin; C034020:anthracene
keywords: PEG; conjugation; modeling; spectroscopy; thermodynamic; trypsin; trypsin inhibitor