A complete cDNA coding for the sequence of glycinin A₂B_1a subunit precursor

Abstract

Analysis of the A2B,. subunit precursor, one of the AZ-subunit family of glycinin, the main storage protein of soybean, revealed that it is composed of a signal peptide segment (18 amino acids), the A2 acidic polypeptide (282 amino acids), followed by the B,. basic polypeptide (185 amino acids). There was overall 63% homology between this subunit complex and pea legumin, which is an analogous protein to glycinin. As this degree of homology is rather higher than that in the A,B, subunit, one of the A, subunit family, it seems that the genes encoding the A2 subunit family are phylogenetically more strongly related to the legumin genes. Soybean I1 S storage protein Glycinin

Nucleotide sequence of cloned cDNA coding for pumpkin 11‐S globulin β subunit

“…4). This agrees with the finding that the signal sequences of soybean glycinin A3B4 and A5A4B3 precursors contain one basic amino acid, lysine, at position 3 [25]. Two cysteine residues are also found at similar positions in the signal sequences of both pumpkin preproglobulin and glycinin precursors (Fig.…”

“…Since the C-terminal amino acid sequence of the y chain has not been determined, the possibility that a linking peptide exists between y and 6 chains can not be discounted. It has been reported that the A and B chain sequences of the preproprotein precursor of castor bean ricin are separated by a 12-amino-acid linking region [24] but that the glycinin A3 and B4 chains are joined directly without a linking region [25].…”

“…5). Proproteins of glycinin [25], legumin [27], vicilin [28], ricin [24] and concanavalin A [29] which are localized in protein bodies are also known to be cleaved posttranslationally after an asparagine residue. Recently we have demonstrated the presence of a unique thiol protease which catalyzes the post-translational cleavage of proproteins in vacuoles or protein bodies of several species [7].…”

High-level Expression, Purification and Functional Properties of Soybean Proglycinin fromEscherichia coli

“…7 -9 ) The following subunits have been identified: A 1a B 1b , A 1b B 2 , A 2 B 1a , A 3 B 4 and A s A 4 B 3 . S , [12][13][14][15][16][17] These subunits are classified as the Al type (AlaB Ib , A lb B 2 , A 2 B la ) and the A 3 type (A 3 B 4 , A s A 4 B 3 ) according to the similarity of N-terminal amino acid sequences. 7 ,10) The nutritional quality of the Al type is superior to that of the others.…”

Expression of soybean glycinin subunit precursor cDNAs in Escherichia coli

“…The purified cDNA fragments were ligated to the NcoI/PstI-cut pKK233-2 expression vector, followed by transfection of E. coli RR1 as described by Dagert and Ehrlich [7]. Transformants were selected by growth on ampicillin, followed by colony hybridizations using 32p-labeled cDNA inserts derived from AzBla and AlaBlb clones [3,5]. After confirmation of the junction region between glycinin cDNA and the expression vector by nucleotide sequencing [8] in those recombinants, the resulting recombinant plasmids, designated pKGAzBlal3 and pKGAlaBlb6, were employed for the expression experiment of AzB~ and AlaB~b subunit precursors of glycinin, respectively.…”