title: Interactions of hepatitis B core antigen and peptide inhibitors.
abstract: The core protein (HBcAg) of hepatitis B virus (HBV) has been shown to interact with the large surface antigen during HBV morphogenesis, and these interactions can be blocked by small peptides selected from either linear or constrained phage display peptide libraries. The association of HBcAg with peptide inhibitors was quantitatively evaluated by isothermal titration calorimetry. The thermodynamic data show that the interaction between HBcAg and peptide MHRSLLGRMKGA is enthalpy-driven and occurs at a 3:1 stoichiometry and dissociation constant (Kd) value of 79.4 muM. However, peptide WSFFSNI displays a higher binding affinity for HBcAg with a Kd value of 18.5 muM when compared to peptide MHRSLLGRMKGA. A combinatorial approach using chemical cross-linking and surface-enhanced laser desorption/ionization-time-of-flight-mass spectrometry shows that the Lys of peptide MHRSLLGRMKGA interacted either with D64, E77, or D78 of HBcAg.
authors.affiliation: Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
authors.forename: Kah Fai
authors.initials: KF
authors.lastname: Tang
authors.forename: Mohd Puad
authors.initials: MP
authors.lastname: Abdullah
authors.forename: Khatijah
authors.initials: K
authors.lastname: Yusoff
authors.forename: Wen Siang
authors.initials: WS
authors.lastname: Tan
mesh_terms: D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry; D006512:Hepatitis B Core Antigens / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics; D014357:Trypsin / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D006512:Hepatitis B Core Antigens; D009842:Oligopeptides; C525464:methionyl-histidyl-arginyl-seryl-leucyl-leucyl-glycyl-arginyl-methinoyl-lysyl-glycyl-alanine; D014357:Trypsin