The defensive functions of plant inhibitors are not restricted to insect enzyme inhibition.
Three plant proteinase inhibitors BbKI (kallikrein inhibitor) and BbCI (cruzipain inhibitor) from Bauhinia bauhinioides, and a BrTI (trypsin inhibitor) from B. rufa, were examined for other effects in Callosobruchus maculatus development; of these only BrTI affected bruchid emergence. BrTI and BbKI share 81% identities in their primary sequences and the major differences between them are the regions comprising the RGD and RGE motifs in BrTI. These sequences were shown to be essential for BrTI insecticidal activity, since a modified BbKI [that is a recombinant form (BbKIm) with some amino acid residues replaced by those found in BrTI sequence] also strongly inhibited insect development. By using synthetic peptides related to the BrTI sequence, YLEAPVARGDGGLA-NH2 (RGE) and IVYYPDRGETGL-NH2 (RGE), it was found that the peptide with an RGE sequence was able to block normal development of C. maculatus larvae (ED(50) 0.16% and LD(50) 0.09%), this being even more effective than the native protein.
Sumikawa
Joana Tomomi
JT
Department of Biochemistry, Universidade Federal de São Paulo, Rua Três de Maio, 100 Vila Clementino, CEP 04044-020, São Paulo, SP, Brazil.
Brito
Marlon Vilela de
MV
Macedo
Maria Ligia Rodrigues
ML
Uchoa
Adriana F
AF
Miranda
Antonio
A
Araujo
Ana Paula U
AP
Silva-Lucca
Rosemeire A
RA
Sampaio
Misako Uemura
MU
Oliva
Maria Luiza Vilela
ML
D000595:Amino Acid Sequence; D000818:Animals; D036481:Bauhinia / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001517:Coleoptera / Q000254:growth & development*; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D017343:Genes, Plant; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism*; D007610:Kallikreins / Q000037:antagonists & inhibitors; D007814:Larva / Q000254:growth & development; D008018:Life Cycle Stages; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010447:Peptide Hydrolases / Q000378:metabolism*; D010455:Peptides; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D007306:Insecticides; D010455:Peptides; D010940:Plant Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D014361:Trypsin Inhibitors; D010447:Peptide Hydrolases; D007610:Kallikreins; D003546:Cysteine Endopeptidases; C063214:cruzipain