Structural characterization of an alpha-amylase inhibitor from a wild common bean (Phaseolus vulgaris): insight into the common structural features of leguminous alpha-amylase inhibitors.
The primary structures of two subunits of an alpha-amylase inhibitor (alpha AI-2) from a wild common bean (Phaseolus vulgaris) were revealed by a comparison of the amino acid sequence previously deduced from the nucleotide sequence with the amino- and carboxyl-terminal amino acid sequences determined by conventional methods. The polypeptide molecular weight of alpha AI-2 obtained by the light-scattering technique, considered together with the sequence molecular weights revealed for the subunits, indicated that alpha AI-2 has the subunit stoichiometry of an alpha 2 beta 2 complex. These structural features were closely similar to those recently elucidated for a white kidney bean (P. vulgaris) alpha-amylase inhibitor, which is quite different in the inhibitory specificity from alpha AI-2. The post-translational processing of the precursor glycoproteins to form the tetrameric structure appeared to require an Arg residue close to the processing site. Further, the proper associations of the subunits into the tetrameric structures seemed to be strictly controlled by a few amino acids on the subunit interfaces.
Nakaguchi
T
T
Department of Applied Biological Chemistry, College of Agriculture, Osaka Perfecture University.
Arakawa
T
T
Philo
J S
JS
Wen
J
J
Ishimoto
M
M
Yamaguchi
H
H
D000595:Amino Acid Sequence; D002241:Carbohydrates / Q000737:chemistry; D002850:Chromatography, Gel; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D007887:Fabaceae; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D008970:Molecular Weight; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D010946:Plants, Medicinal; D011487:Protein Conformation; D011489:Protein Denaturation; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012542:Scattering, Radiation; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D002241:Carbohydrates; D004791:Enzyme Inhibitors; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C061510:alpha-amylase inhibitor, Phaseolus vulgaris; D000516:alpha-Amylases