title: Immune peptides modelling of Culex pipiens sp by in silico methods.
abstract: BACKGROUND
  In the past 60 years, antibiotics have been critical in the fight against infectious diseases caused by bacteria and other microbes. Development of resistance to the antibiotics is emerging as a major public health issue which has resulted in the search for new antibiotics in order to maintain a pool of effective drugs at all times. Currently, there is a great interest in cationic peptides as antibiotics. These are reported to destroy the host cell membrane rather interacting with the other cell components, which may not face emergence of resistance. In mosquitoes, peptides like cecropin, defensin and gambicin reported to have inhibitory effect on bacteria, fungi and parasites. These peptides are well-characterized at both the biochemical and molecular level from Anopheles and Culex species, yet their 3D structures were not reported.
  
  
  METHODS
  Defensin, cecropin and gambicin immune peptides of Culex pipiens was characterised to have antiparasitic, antibacterial and antifungal activities. Since the crystal structure of defensin, cecropin and gambicin are not yet available their 3D structures were determined using homology modeling and Rosetta fragment insertion methods and were validated.
  
  
  RESULTS
  Stereo chemical evaluation indicated that defensin and gambicin showed that 100% residues of constructed model lie in the most favoured and allowed regions. Cecropin iso-forms A and B showed 100% while C showed 97.6% residues that lie in most favoured and allowed regions, which indicated quality models.
  
  
  CONCLUSIONS
  Predicted model provide insight into their structure and aid in the development of novel antibiotic peptides.
authors.affiliation: Bioinformatics Group, Biology Division, Indian Institute of Chemical Technology (CSIR), Hyderabad, India.
authors.forename: Nayanoori
authors.initials: N
authors.lastname: Harikrishna
authors.forename: Mutheneni Srinivasa
authors.initials: MS
authors.lastname: Rao
authors.forename: Upadhyayula Suryanarayana
authors.initials: US
authors.lastname: Murty
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D054807:Cecropins / Q000737:chemistry / Q000494:pharmacology; D003198:Computer Simulation; D003465:Culex / Q000737:chemistry*; D023082:Defensins / Q000737:chemistry / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects*; D019476:Insect Proteins / Q000737:chemistry / Q000494:pharmacology; D008958:Models, Molecular; D010271:Parasites / Q000187:drug effects*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D023181:Antimicrobial Cationic Peptides; D054807:Cecropins; D023082:Defensins; D019476:Insect Proteins; C031162:cecropin B protein, Insecta