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1.
Biomed Res Int ; 2014: 981923, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24901004

RESUMO

Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) by p-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.


Assuntos
Alquilação/imunologia , Anticorpos/imunologia , Bothrops/metabolismo , Venenos de Crotalídeos/metabolismo , Histidina/metabolismo , Fosfolipases A2/metabolismo , Animais , Antivenenos/imunologia , Antivenenos/metabolismo , Bothrops/imunologia , Reações Cruzadas/imunologia , Venenos de Crotalídeos/imunologia , Histidina/imunologia , Masculino , Camundongos , Músculo Esquelético/imunologia , Músculo Esquelético/metabolismo , Fosfolipases A2/imunologia
2.
Acta Crystallogr Sect F Struct Biol Cryst Commun ; 65(Pt 10): 1011-3, 2009 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-19851009

RESUMO

Crotoxin B is a basic phospholipase A(2) found in the venom of several Crotalus durissus ssp. rattlesnakes and is one of the subunits that constitute crotoxin, the main component of the venom of these snakes. This heterodimeric toxin is related to important envenomation effects such as neurological disorders, myotoxicity and renal failure. Although crotoxin was first crystallized in 1938, the first structural data only became available in 2007 (for crotoxin B from C. durissus terrificus) and showed an ambiguous result for the biological assembly, which could be either dimeric or tetrameric. In this work, the crystallization, X-ray diffraction data collection at 2.2 A resolution and molecular-replacement solution of a dimeric complex formed by two crotoxin B isoforms from C. durissus collilineatus venom is presented.


Assuntos
Crotoxina/química , Animais , Venenos de Crotalídeos/química , Crotoxina/isolamento & purificação , Cristalização , Cristalografia por Raios X , Dimerização , Fosfolipases A2/química , Estrutura Quaternária de Proteína
3.
Artigo em Inglês | MEDLINE | ID: mdl-16754993

RESUMO

For the first time, a non-catalytic and myotoxic Lys49-PLA2 (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities. This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA2s, and other toxicological activities of Lys49-PLA2s.


Assuntos
Acetofenonas/química , Venenos de Crotalídeos/química , Fosfolipases A/química , Animais , Bothrops , Catálise , Cristalização/métodos , Histidina/química , Fosfolipases A/metabolismo , Fosfolipases A/toxicidade , Fosfolipases A2 , Solventes , Difração de Raios X
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