Assembly of Agrostemma githago (corn-cockle) storage proteins and their precursor proteins into oligomers

Abstract

The major fraction of seed storage proteins of Agrostemma githago (corn-cockle), a non-leguminous dicot, occurs as material with S20,w values of approximately 11S and approximately 2S, and a minor fraction as oligomers with S20,w values of approximately 6.5S. The 11S proteins are of the legumin type and consist of disulphide-linked α- and β-subunits of Mr approximately 39 000 and approximately 23 000 respectively. The oligomeric assembly of the precursor polypeptides of the 11S proteins was examined. The approximately 65 000-Mr precursor polypeptides of two 11S proteins, which consist of 38 000-25 000-Mr subunits and 36 000-22 000-Mr subunits respectively, were assembled into oligomers of approximately 7S and subsequently cleaved. Thereafter the 11S oligomer was formed. The 88 000-Mr precursor of a third 11S protein, which consists of 41 000-23 000-Mr subunits, was assembled into an approximately 8S oligomer and then cleaved, yielding two disulphide-linked intermediates of Mr 59 000 and 24 000. Thereafter, the 11S oligomer was formed. Processing of the 59 000-Mr to the 41 000-Mr polypeptide occurred both in the 8S and in the 11S form.

An Electrophoretic Analysis of the Seed Proteins of some Vicia L. Species from Northeast Anatolia (Turkey)

“…In some species of Leguminasae, such as Vicia faba L. and Pisum sativum L., the 11 and 12S proteins were described as the major seed proteins (Derbyshire et al, 1976). 30-40 and 20 kDa proteins were recognized in many dicot and monocot species (De Klerk and Engelen, 1985;Fischer and Schopfer, 1988;Hasegawa et al, 1978;Jensen, 1984;Jensen and Buttner, 1981;Konishi et al, 1985;Simon et al, 1985). Similarly, we determined most of the soluble proteins between the ranges at 30-40 and 20 kDa.…”

“…Similar proteins with the significant legumin characters (acidic subunits of Mr =c. 30-40 KD, basic subunits of Mr = c. 20 KD, linked together by S-S bridges and forming hexametric molecules in the storage tisues) have also been recognized as major storage proteins in many dicot and monocot species (De Klerk and Engelen, 1985;Fischer and Schopfer, 1988;Hasegawa et al, 1978;Jensen, 1984;Jensen and Buttner, 1981;Konishi et al, 1985;Simon et al, 1985). In this investigation we analysed the occurence of the soluble and insoluble proteins in some Vicia species collected from Northeast Anatolia (Turkey) were surveyed.…”