Open AccessAmino acid sequence of a crystalline seed albumin (winged bean albumin‐1) from Psophocarpus tetragonolobus (L.) DC
Author(s) -
KORTT Alexander A.,
STRIKE Philip M.,
JERSEY John
Publication year - 1989
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1989.tb14739.x
Subject(s) - trypsin , trypsin inhibitor , storage protein , amino acid , albumin , peptide sequence , molecular mass , biochemistry , kunitz sti protease inhibitor , protein secondary structure , biology , globulin , chemistry , enzyme , gene , immunology
The complete amino acid sequence of winged bean albumin‐1 (WBA‐1) of Psophocarpus tetragonolobus (L.) DC has been determined. The protein consists of a single polypeptide chain of 175 amino acid residues, with one disulfide bond, corresponding to a molecular mass of 19333 Da. WBA‐1 was found to be homologous with the Kunitz‐type seed trypsin inhibitors. The similarity between WBA‐1 and the trypsin inhibitors from soybean and winged bean was 38% and 28%, respectively; similarity was most marked in the C‐terminal third of the sequence with identities of 47% and 37%, respectively. Significant similarity was found also between the 2S Kunitz‐type proteins and the carboxy‐terminal region of the 7S storage globulins, suggesting that these two groups of proteins are related and may have evolved from a common ancestral precursor. Circular dichroism measurements suggest a high content of β sheet (52%) while secondary structure predictions based on amino acid sequence indicate a similar content and distribution of β sheet to that found for soybean trypsin inhibitor by X‐ray diffraction studies.