A recombinant form of chagasin from Trypanosoma cruzi: inhibitory activity on insect cysteine proteinases.
BACKGROUND
The activity of the major digestive cysteine proteinase detected in the intestinal tract of larvae of the bean weevil, Acanthoscelides obtectus (Say), was efficiently inhibited by the well-characterized cysteine proteinase synthetic inhibitor E-64 and also by a recombinant form of chagasin (r-chagasin), a tight-binding cysteine proteinase inhibitor protein from Trypanosoma cruzi.


RESULTS
Incorporation of r-chagasin into an artificial diet system at 0.1 g kg(-1) retarded growth rate, decreased larval survival and led to complete mortality of A. obtectus at the end of the trial. The observed differences in growth rates occurred particularly in the first and second development stages. Artificial seeds containing high levels of r-chagasin (0.5-30 g kg(-1)) completely inhibited larval penetration.


CONCLUSIONS
Together, the results reported in this paper support the hypothesis that the inhibitory activity of r-chagasin towards the major insect gut cysteine proteinase in vitro and in vivo is an accurate prediction of its insecticidal effects. The selectivity of this inhibitor against insect digestive proteinases supports the key role in parasite virulence by affecting the endogenous proteinase activity in its natural host.
Dos Santos Monteiro
Ana Carolina
AC
Embrapa Recursos Genéticos e Biotecnologia, PqEB, Final W5 Norte, 70770-900, Brasília, DF, Brazil.
de Oliveira Neto
Osmundo Brilhante
OB
Del Sarto
Rafael Perseghini
RP
de Magalhães
Mariana Torquato Q
MT
Lima
Janaina Nascimento
JN
Lacerda
Ariane Ferreira
AF
Oliveira
Raquel Sampaio
RS
Scharfstein
Julio
J
da Silva
Maria Cristina Mattar
MC
Valencia
Jorge W Arboleda
JW
Jiménez
Arnubio Valencia
AV
Grossi-de-Sa
Maria Fatima
MF
D000818:Animals; D001517:Coleoptera / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D041981:Gastrointestinal Tract / Q000201:enzymology; D019476:Insect Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007814:Larva / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D010572:Pest Control, Biological; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology
D015853:Cysteine Proteinase Inhibitors; D019476:Insect Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C435145:chagasin, Trypanosoma; D003546:Cysteine Endopeptidases