Data/hora: 01/06/2024 04:41:31

Biblioteca(s): | Embrapa Agricultura Digital; Embrapa Recursos Genéticos e Biotecnologia.
Data corrente: | 10/06/2005
Data da última atualização: | 03/12/2007
Autoria: | SILVA, M. C. M. da; MELLO, L. V.; COUTINHO, M. V.; RIGDEN, D. J.; NESHICH, G.; CHRISPEELS, M. J.; GROSSI-DE-SÁ, M. F.
Título: | Mutants of common bean alpha-amylase inhibitor-2 as an approach to investigate binding specificity to alpha-amylases.
Ano de publicação: | 2004
Fonte/Imprenta: | Pesquisa Agropecuária Brasileira, Brasília, DF, v. 39, n. 3, p. 201-208, mar. 2004.

Idioma:

Inglês
Português

Conteúdo: | Despite the presence of a family of defense proteins, Phaseolus vulgaris can be attacked by bruchid insects resulting in serious damage to stored grains. The two distinct active forms of a-amylase inhibitors, a-AI1 and a-AI2, in P. vulgaris show different specificity toward a-amylases. Zabrotes subfasciatus a-amylase is inhibited by a-AI2 but not by a-AI1. In contrast, porcine a-amylase is inhibited by a-AI1 but not by a-AI2. The objective of this work was to understand the molecular basis of the specificity of two inhibitors in P. vulgaris (a-AI1 and a-AI2) in relation to a-amylases. Mutants of a-AI2 were made and expressed in tobacco plants. The results showed that all the a-AI2 mutant inhibitors lost their activity against the insect a-amylases but none exhibited activity toward the mammalian a-amylase. The replacement of His33 of a-AI2 with the a-AI1-like sequence Ser-Tyr-Asn abolished inhibition of Z. subfasciatus a-amylase. From structural modeling, the conclusion is that the size and complexity of the amylase-inhibitor interface explain why mutation of the N-terminal loop and resultant abolition of Z. subfasciatus a-amylase inhibition are not accompanied by gain of inhibitory activity against porcine a-amylase.
Palavras-Chave: | Alfa amilase; Especificidade de interação; Inibidores de a-amilases; Modelagem molecular; mutagênese sítio-dirigida.
Thesagro: | Inibidor de Enzima; Phaseolus Vulgaris.
Categoria do assunto: | --
URL: | http://ainfo.cnptia.embrapa.br/digital/bitstream/CNPTIA/11568/1/v39n03a01.pdf
Registro original: | Embrapa Agricultura Digital (CNPTIA)

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CNPTIA - (11568-1) - UPC - AP - -- -  -  -  - DIS
CENARGEN - (25119-1) - UPC - AP - -- - 630.5 -  -  - DIS