A lectin gene encodes the alpha-amylase inhibitor of the common bean.
AUTOR(ES)
Moreno, J
RESUMO
An alpha-amylase inhibitor that inhibits insect and mammalian alpha-amylases but not plant alpha-amylases, is present in seeds of the common bean (Phaseolus vulgaris). We have purified the alpha-amylase inhibitor by using a selective heat treatment in acidic medium and affinity chromatography with porcine pancreas alpha-amylase coupled to agarose. Under sodium dodecyl sulfate gel electrophoresis, the purified inhibitor gave rise to five bands with mobilities corresponding to molecular masses ranging from 14 to 19 kDa. N-terminal sequencing (up to 15 amino acids) of the polypeptides obtained from these bands resulted in only two different sequences matching two stretches of the amino acid sequence deduced from an already described lectin gene [Hoffman, L. M. (1984) J. Mol. Appl. Gen. 2,447-453]. This gene is different from but closely related to the genes that code for phytohemagglutinin, the major lectin of bean. Further evidence based on amino acid composition, identification of a precursor, and recognition of the product of the gene (expressed in Escherichia coli) by an anti-alpha-amylase inhibitor serum confirms that the inhibitor is encoded by this or a closely related lectin gene. This finding assigns a biological function, which has been described at the molecular level, to a plant lectin gene product and supports the defense role postulated for seed lectins. The lack of homology with other families of enzyme inhibitors suggests that this may be the first member of a new family of plant enzyme inhibitors.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=298176Documentos Relacionados
- Protective mechanism of the Mexican bean weevil against high levels of alpha-amylase inhibitor in the common bean.
- Mutants of common bean alpha-amylase inhibitor-2 as an approach to investigate binding specificity to alpha-amylases.
- Mutants of common bean alpha-amylase inhibitor-2 as an approach to investigate binding specificity to alpha-amylases.
- Activation of bean (Phaseolus vulgaris) alpha-amylase inhibitor requires proteolytic processing of the proprotein.
- Complete nucleotide sequence of an alpha-amylase gene from Bacillus subtilis 2633, an alpha-amylase extrahyperproducing strain.