title: Evaluation of the crystal structure of a fimbrillin (FimA) from Porphyromonas gingivalis as a therapeutic target for photo-activated disinfection with toluidine blue O.
abstract: BACKGROUND
  Porphyromonas gingivalis is one of the etiological agents in the initiation of combined periodontal-endodontic (perio-endo) lesions. Successful treatment of perio-endo lesions with photo-activated disinfection (PAD) as a novel therapeutic approach depends on the selection of an appropriate target site, specific photosensitizer (PS), and wavelength of light. Since the fimbrillin (FimA) is the most important pathogenic agent in P. gingivalis it was evaluated as a target site against PAD with toluidine blue O (TBO) as a PS.
  
  
  METHODS
  We evaluated the potential of FimA using a number of bioinformatic tools and computer simulation molecular modeling. In silico analysis was done to predict the hierarchical nature of structure, topology, backbone, physicochemical properties, and functional characterization of FimA.
  
  
  RESULTS
  The predicted structure of FimA exhibited that it is an anionic protein with negative charge (-7.00) in pH7 and random coil which dominates other secondary structures located outside the cell. It has three motifs with seven ligand binding site residues and one active site residue which can be a site of interaction for cationic TBO.
  
  
  CONCLUSIONS
  Based on the results of this study cationic TBO tends to interact with FimA during PAD as a major target to increase the efficiency of treatment of perio-endo lesions.
authors.affiliation: Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Pourhajibagher
authors.affiliation: Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: abahador@sina.tums.ac.ir.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
mesh_terms: D003198:Computer Simulation; D004203:Disinfection / Q000379:methods; D036781:Fimbriae Proteins / Q000187:drug effects*; D006801:Humans; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects*; D014048:Tolonium Chloride / Q000494:pharmacology*
chemical_list: D017319:Photosensitizing Agents; C063055:fimbrillin; D036781:Fimbriae Proteins; D014048:Tolonium Chloride
keywords: Bioinformatics; FimA; In silico; Periodontal-endodontic lesions; Porphyromonas gingivalis; Toluidine blue O; Virulence factor