title: Astacin-like metalloproteases are a gene family of toxins present in the venom of different species of the brown spider (genus Loxosceles).
abstract: Brown spiders have a worldwide distribution, and their venom has a complex composition containing many different molecules. Herein, we report the existence of a family of astacin-like metalloprotease toxins in Loxosceles intermedia venom, as well as in the venom of different species of Loxosceles. Using a cDNA library from the L. intermedia venom gland, we cloned two novel cDNAs encoding astacin-like metalloprotease toxins, LALP2 and LALP3. Using an anti-serum against the previously described astacin-like toxin in L. intermedia venom (LALP1), we detected the presence of immunologically-related toxins in the venoms of L. intermedia, Loxosceles laeta, and Loxosceles gaucho. Zymographic experiments showed gelatinolytic activity of crude venoms of L. intermedia, L. laeta, and L. gaucho (which could be inhibited by the divalent metal chelator 1,10-phenanthroline) at electrophoretic mobilities identical to those reported for immunological cross-reactivity. Moreover, mRNAs extracted from L. laeta and L. gaucho venom glands were screened for astacin-like metalloproteases, and cDNAs obtained using LALP1-specific primers were sequenced, and their deduced amino acid sequences confirmed they were members of the astacin family with the family signatures (HEXXHXXGXXHE and MXY), LALP4 and LALP5, respectively. Sequence comparison of deduced amino acid sequences revealed that LALP2, LALP3, LALP4, and LALP5 are related to the astacin family. This study identified the existence of gene family of astacin-like toxins in the venoms of brown spiders and raises the possibility that these molecules are involved in the deleterious effects triggered by the venom.
authors.affiliation: Department of Cell Biology, Federal University of Paraná, Brazil.
authors.forename: Dilza
authors.initials: D
authors.lastname: Trevisan-Silva
authors.forename: Luiza H
authors.initials: LH
authors.lastname: Gremski
authors.forename: Olga M
authors.initials: OM
authors.lastname: Chaim
authors.forename: Rafael B
authors.initials: RB
authors.lastname: da Silveira
authors.forename: Gabriel O
authors.initials: GO
authors.lastname: Meissner
authors.forename: Oldemir C
authors.initials: OC
authors.lastname: Mangili
authors.forename: Katia C
authors.initials: KC
authors.lastname: Barbaro
authors.forename: Waldemiro
authors.initials: W
authors.lastname: Gremski
authors.forename: Silvio S
authors.initials: SS
authors.lastname: Veiga
authors.forename: Andrea
authors.initials: A
authors.lastname: Senff-Ribeiro
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D003429:Cross Reactions; D018076:DNA, Complementary / Q000235:genetics; D005780:Gelatin / Q000378:metabolism; D006801:Humans; D008666:Metalloendopeptidases / Q000737:chemistry*; D045726:Metalloproteases / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010618:Phenanthrolines / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013111:Spider Venoms / Q000201:enzymology* / Q000235:genetics; D013112:Spiders / Q000201:enzymology* / Q000235:genetics
chemical_list: D000906:Antibodies; D018076:DNA, Complementary; D010618:Phenanthrolines; D012333:RNA, Messenger; D013111:Spider Venoms; C055161:loxosceles venom; D005780:Gelatin; D010727:Phosphoric Diester Hydrolases; D045726:Metalloproteases; D008666:Metalloendopeptidases; C071288:astacin; C025205:1,10-phenanthroline