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Structural Basis for the Inhibition of a Phospholipase A2-Like Toxin by Caffeic and Aristolochic Acids.

Fernandes CA, Cardoso FF, Cavalcante WG, Soares AM, Dal-Pai M, Gallacci M, Fontes MR - PLoS ONE (2015)

Bottom Line: Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability.This leads to economic and social problems, especially in developing countries.These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane.

View Article: PubMed Central - PubMed

Affiliation: Dep. de Física e Biofísica, Instituto de Biociências, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil; Instituto Nacional de Ciência e Tecnologia em Toxinas, CNPq, São Paulo, São Paulo, Brazil.

ABSTRACT
One of the main challenges in toxicology today is to develop therapeutic alternatives for the treatment of snake venom injuries that are not efficiently neutralized by conventional serum therapy. Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability. This leads to economic and social problems, especially in developing countries. In this work, we performed structural and functional studies with Piratoxin-I, a Lys49-PLA2 from Bothropspirajai venom, complexed with two compounds present in several plants used in folk medicine against snakebites. These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane. Our results corroborate the previously proposed mechanism of action of PLA2s-like and provide insights for the design of structure-based inhibitors that could prevent the permanent injuries caused by these proteins in snakebite victims.

No MeSH data available.


Related in: MedlinePlus

Dimeric structures of (A) PrTX-I complexed to aristolochic acid (PrTX-I/AA) and (B) PrTX-I complexed to caffeic acid (PrTX-I/CA) shown as a cartoon representation.PEG molecules, sulfate ions,AA and CAare indicatedby sticks (in cyan, yellow, blue and green, respectively). In yellow sticks are also highlighted the aminoacids that compose MDiS (Leu121)andMDoS (Lys20, Lys155, Arg118) regions, which interact with AA and CA, respectively. (C) Cα superposition of apo-PrTX-I, PrTX-I/AA, PrTX-I/CA and PrTX-I complexed to rosmarinic acid (PrTX-I/RA) (monomers A and B, respectively) highlighting the most important structural deviations between them.
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pone.0133370.g004: Dimeric structures of (A) PrTX-I complexed to aristolochic acid (PrTX-I/AA) and (B) PrTX-I complexed to caffeic acid (PrTX-I/CA) shown as a cartoon representation.PEG molecules, sulfate ions,AA and CAare indicatedby sticks (in cyan, yellow, blue and green, respectively). In yellow sticks are also highlighted the aminoacids that compose MDiS (Leu121)andMDoS (Lys20, Lys155, Arg118) regions, which interact with AA and CA, respectively. (C) Cα superposition of apo-PrTX-I, PrTX-I/AA, PrTX-I/CA and PrTX-I complexed to rosmarinic acid (PrTX-I/RA) (monomers A and B, respectively) highlighting the most important structural deviations between them.

Mentions: Crystals of both complexesdiffracted at high resolution (Table 1) and classified as belonging to the P21212or P21 space groups for PrTX-I/AA and PrTX-I/CA, respectively. The refinements converged to final R values of 17.3% (Rfree = 23.5%) and 18.3% (Rfree = 22.9%), respectively, for PrTX-I/AA and PrTX-I/CA. The final models (Fig 4) are of a stereochemical quality expected for structures with the same resolution, as indicated by r.m.s.d bonds, r.m.s.d. angles and Ramachandran plot analyses (Table 1). Both structures have seven disulfide bridges in each monomer with the following structural features: (i) an N-terminal α-helix; (ii) a “short” helix; (iii) a Ca2+ binding loop; (iv) two anti-parallel α-helices (2 and 3); (v) two short strands of an anti-parallel β-sheet (β-wing); and (vi) a C-terminal loop (Fig 4), similar to all other class II PLA2s [44,45].


Structural Basis for the Inhibition of a Phospholipase A2-Like Toxin by Caffeic and Aristolochic Acids.

Fernandes CA, Cardoso FF, Cavalcante WG, Soares AM, Dal-Pai M, Gallacci M, Fontes MR - PLoS ONE (2015)

Dimeric structures of (A) PrTX-I complexed to aristolochic acid (PrTX-I/AA) and (B) PrTX-I complexed to caffeic acid (PrTX-I/CA) shown as a cartoon representation.PEG molecules, sulfate ions,AA and CAare indicatedby sticks (in cyan, yellow, blue and green, respectively). In yellow sticks are also highlighted the aminoacids that compose MDiS (Leu121)andMDoS (Lys20, Lys155, Arg118) regions, which interact with AA and CA, respectively. (C) Cα superposition of apo-PrTX-I, PrTX-I/AA, PrTX-I/CA and PrTX-I complexed to rosmarinic acid (PrTX-I/RA) (monomers A and B, respectively) highlighting the most important structural deviations between them.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508052&req=5

pone.0133370.g004: Dimeric structures of (A) PrTX-I complexed to aristolochic acid (PrTX-I/AA) and (B) PrTX-I complexed to caffeic acid (PrTX-I/CA) shown as a cartoon representation.PEG molecules, sulfate ions,AA and CAare indicatedby sticks (in cyan, yellow, blue and green, respectively). In yellow sticks are also highlighted the aminoacids that compose MDiS (Leu121)andMDoS (Lys20, Lys155, Arg118) regions, which interact with AA and CA, respectively. (C) Cα superposition of apo-PrTX-I, PrTX-I/AA, PrTX-I/CA and PrTX-I complexed to rosmarinic acid (PrTX-I/RA) (monomers A and B, respectively) highlighting the most important structural deviations between them.
Mentions: Crystals of both complexesdiffracted at high resolution (Table 1) and classified as belonging to the P21212or P21 space groups for PrTX-I/AA and PrTX-I/CA, respectively. The refinements converged to final R values of 17.3% (Rfree = 23.5%) and 18.3% (Rfree = 22.9%), respectively, for PrTX-I/AA and PrTX-I/CA. The final models (Fig 4) are of a stereochemical quality expected for structures with the same resolution, as indicated by r.m.s.d bonds, r.m.s.d. angles and Ramachandran plot analyses (Table 1). Both structures have seven disulfide bridges in each monomer with the following structural features: (i) an N-terminal α-helix; (ii) a “short” helix; (iii) a Ca2+ binding loop; (iv) two anti-parallel α-helices (2 and 3); (v) two short strands of an anti-parallel β-sheet (β-wing); and (vi) a C-terminal loop (Fig 4), similar to all other class II PLA2s [44,45].

Bottom Line: Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability.This leads to economic and social problems, especially in developing countries.These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane.

View Article: PubMed Central - PubMed

Affiliation: Dep. de Física e Biofísica, Instituto de Biociências, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil; Instituto Nacional de Ciência e Tecnologia em Toxinas, CNPq, São Paulo, São Paulo, Brazil.

ABSTRACT
One of the main challenges in toxicology today is to develop therapeutic alternatives for the treatment of snake venom injuries that are not efficiently neutralized by conventional serum therapy. Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability. This leads to economic and social problems, especially in developing countries. In this work, we performed structural and functional studies with Piratoxin-I, a Lys49-PLA2 from Bothropspirajai venom, complexed with two compounds present in several plants used in folk medicine against snakebites. These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane. Our results corroborate the previously proposed mechanism of action of PLA2s-like and provide insights for the design of structure-based inhibitors that could prevent the permanent injuries caused by these proteins in snakebite victims.

No MeSH data available.


Related in: MedlinePlus