title: Structure-function relationships of the peptide Paulistine: a novel toxin from the venom of the social wasp Polybia paulista.
abstract: BACKGROUND
  The peptide Paulistine was isolated from the venom of wasp Polybia paulista. This peptide exists under a natural equilibrium between the forms: oxidised - with an intra-molecular disulphide bridge; and reduced - in which the thiol groups of the cysteine residues do not form the disulphide bridge. The biological activities of both forms of the peptide are unknown up to now.
  
  
  METHODS
  Both forms of Paulistine were synthesised and the thiol groups of the reduced form were protected with the acetamidemethyl group [Acm-Paulistine] to prevent re-oxidation. The structure/activity relationships of the two forms were investigated, taking into account the importance of the disulphide bridge.
  
  
  RESULTS
  Paulistine has a more compact structure, while Acm-Paulistine has a more expanded conformation. Bioassays reported that Paulistine caused hyperalgesia by interacting with the receptors of lipid mediators involved in the cyclooxygenase type II pathway, while Acm-Paullistine also caused hyperalgesia, but mediated by receptors involved in the participation of prostanoids in the cyclooxygenase type II pathway.
  
  
  CONCLUSIONS
  The acetamidemethylation of the thiol groups of cysteine residues caused small structural changes, which in turn may have affected some physicochemical properties of the Paulistine. Thus, the dissociation of the hyperalgesy from the edematogenic effect when the actions of Paulistine and Acm-Paulistine are compared to each other may be resulting from the influence of the introduction of Acm-group in the structure of Paulistine.
  
  
  CONCLUSIONS
  The peptides Paulistine and Acm-Paulistine may be used as interesting tools to investigate the mechanisms of pain and inflammation in future studies.
authors.affiliation: Department of Biology/CEIS/LSBZ, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, SP, Brazil.
authors.forename: Paulo Cesar
authors.initials: PC
authors.lastname: Gomes
authors.forename: Bibiana Monson
authors.initials: BM
authors.lastname: de Souza
authors.forename: Nathalia Baptista
authors.initials: NB
authors.lastname: Dias
authors.forename: Patrícia
authors.initials: P
authors.lastname: Brigatte
authors.forename: Danilo
authors.initials: D
authors.lastname: Mourelle
authors.forename: Helen Andrade
authors.initials: HA
authors.lastname: Arcuri
authors.forename: Marcia Perez
authors.initials: MP
authors.lastname: dos Santos Cabrera
authors.forename: Rodrigo Guerino
authors.initials: RG
authors.lastname: Stabeli
authors.forename: João Ruggiero
authors.initials: JR
authors.lastname: Neto
authors.forename: Mario Sergio
authors.initials: MS
authors.lastname: Palma
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects*; D002942:Circular Dichroism; D004487:Edema / Q000188:drug therapy* / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D006930:Hyperalgesia / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000737:chemistry* / Q000494:pharmacology; D051381:Rats; D018077:Receptors, Leukotriene / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D014862:Wasp Venoms / Q000494:pharmacology*; D014863:Wasps / Q000737:chemistry / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D010446:Peptide Fragments; D018077:Receptors, Leukotriene; D014862:Wasp Venoms
keywords: Disulphide bridge; Hyperalgesia; Inflammation; Molecular structure; Pain; Wasp venom