title: Natterins, a new class of proteins with kininogenase activity characterized from Thalassophryne nattereri fish venom.
abstract: A novel family of proteins with kininogenase activity and unique primary structure was characterized using combined pharmacological, proteomic and transcriptomic approaches of Thalassophryne nattereri fish venom. The major venom components were isolated and submitted to bioassays corresponding to its main effects: nociception and edema. These activities were mostly located in one fraction (MS3), which was further fractionated. The isolated protein, named natterin, was able to induce edema, nociception and cleave human kininogen and kininogen-derived synthetic peptides, releasing kallidin (Lys-bradykinin). The enzymatic digestion was inhibited by kallikrein inhibitors as Trasylol and TKI. Natterin N-terminal peptide showed no similarity with already known proteins present in databanks. Primary structure of natterin was obtained by a transcriptomic approach using a representative cDNA library constructed from T. nattereri venom glands. Several expressed sequence tags (ESTs) were obtained and processed by bioinformatics revealing a major group (18%) of related sequences unknown to gene or protein sequence databases. This group included sequences showing the N-terminus of isolated natterin and was named Natterin family. Analysis of this family allowed us to identify five related sequences, which we called natterin 1-4 and P. Natterin 1 and 2 sequences include the N-terminus of the isolated natterin. Furthermore, internal peptides of natterin 1-3 were found in major spots of whole venom submitted to mass spectrometry/2DGE. Similarly to the ESTs, the complete sequences of natterins did not show any significant similarity with already described tissue kallikreins, kininogenases or any proteinase, all being entirely new. These data present a new task for the knowledge of the action of kininogenases and may help in understanding the mechanisms of T. nattereri fish envenoming, which is an important medical problem in North and Northeast of Brazil.
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brasil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: G S
authors.initials: GS
authors.lastname: Magalhães
authors.forename: M
authors.initials: M
authors.lastname: Lopes-Ferreira
authors.forename: I L M
authors.initials: IL
authors.lastname: Junqueira-de-Azevedo
authors.forename: P J
authors.initials: PJ
authors.lastname: Spencer
authors.forename: M S
authors.initials: MS
authors.lastname: Araújo
authors.forename: F C V
authors.initials: FC
authors.lastname: Portaro
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.forename: R H
authors.initials: RH
authors.lastname: Valente
authors.forename: L
authors.initials: L
authors.lastname: Juliano
authors.forename: J W
authors.initials: JW
authors.lastname: Fox
authors.forename: P L
authors.initials: PL
authors.lastname: Ho
authors.forename: A M
authors.initials: AM
authors.lastname: Moura-da-Silva
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D024541:Batrachoidiformes / Q000378:metabolism*; D002850:Chromatography, Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D005397:Fish Venoms / Q000737:chemistry / Q000302:isolation & purification*; D005400:Fishes, Poisonous; D015723:Gene Library; D007610:Kallikreins / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D005397:Fish Venoms; D007610:Kallikreins