title: Structural and biological characterization of a crotapotin isoform isolated from Crotalus durissus cascavella venom.
abstract: Envenoming by Crotalus durissus subspecies leads to coagulation disorders, myotoxicity, neurotoxicity and acute renal failure. The most serious systemic alteration and primary cause of death after snakebite is acute renal failure. In this work, we isolated crotapotin, an acid component (Crtp) of crotoxin from Crotalus durissus cascavella venom and we investigated its bactericidal and pro-inflammatory activities as well as its renal effects in rat isolated perfused kidneys. Crtp was bactericidal to the Gram-negative species Xanthomonas axonopodis pv. passiflorae, but was less effective against the Gram-positive Claribacteri ssp, probably because of differences in the cell wall composition. Crtp showed a high amino acid sequence homology with other Crtps described in the literature (around of 90%) and its A and B chains had high conserved regions corresponding to the calcium-binding loop, catalytic site and helix 3 of PLA2. The Crtp showed moderate pro-inflammatory activity and increased significantly the inflammation evoked by PLA2 when co-injected or co-incubated with PLA2. The renal parameters evaluated included the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR) and percent of sodium tubular transport (%TNa+). Crotapotin (5 microg/ml) significantly increased the PP and RVR, whereas the GFR, UF and %TNa+ were unaffected. These results suggest that crotoxin is the main venom component responsible for nephrotoxicity and crotapotin contributes little to this phenomenom. The biological and bactericidal actions of Crtp also suggest that this protein may have functions other than simply acting as a chaperone for PLA2.
authors.affiliation: Department of Biochemistry, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
authors.forename: Daniela G
authors.initials: DG
authors.lastname: de Oliveira
authors.forename: Marcos H
authors.initials: MH
authors.lastname: Toyama
authors.forename: Alice M C
authors.initials: AM
authors.lastname: Martins
authors.forename: Alexandre
authors.initials: A
authors.lastname: Havt
authors.forename: Arlândia C L
authors.initials: AC
authors.lastname: Nobre
authors.forename: Sergio
authors.initials: S
authors.lastname: Marangoni
authors.forename: Paula R
authors.initials: PR
authors.lastname: Câmara
authors.forename: Edson
authors.initials: E
authors.lastname: Antunes
authors.forename: Gilberto
authors.initials: G
authors.lastname: de Nucci
authors.forename: Luis O S
authors.initials: LO
authors.lastname: Beliam
authors.forename: Manassés C
authors.initials: MC
authors.lastname: Fonteles
authors.forename: Helena S A
authors.initials: HS
authors.lastname: Monteiro
mesh_terms: D000192:Actinomycetales / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003435:Crotalid Venoms / Q000737:chemistry*; D003439:Crotoxin / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004487:Edema / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D006614:Hindlimb / Q000187:drug effects / Q000473:pathology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010477:Perfusion; D010741:Phospholipases A / Q000494:pharmacology; D054467:Phospholipases A2; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D016415:Sequence Alignment; D012867:Skin / Q000187:drug effects / Q000473:pathology; D014974:Xanthomonas / Q000187:drug effects
chemical_list: D003435:Crotalid Venoms; D020033:Protein Isoforms; D003439:Crotoxin; D010741:Phospholipases A; D054467:Phospholipases A2