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Potential β‐sheet surfaces of soybean seed proteins
Author(s) -
Rothfus John A.
Publication year - 1995
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02638848
Subject(s) - oleosin , chemistry , residue (chemistry) , tyrosine , side chain , protein subunit , proline , storage protein , polarity (international relations) , biochemistry , biophysics , amino acid , biology , organic chemistry , polymer , cell , gene
Volume and amphiphilicity profiles computed for β‐sheet conformations of soybean seed proteins (the acidic and basic subunits of glycinin, the α subunit of β‐conglycinin, an extensin‐like high‐proline protein, and a lipid body oleosin) were compared to profiles for selected nonseed proteins and random‐sequence polypeptides. The major soy proteins resemble fibrinogen more than silk or collagen but are differentiated from each other by surface polarity. Polarity in acidic glycinin fluctuates somewhat regularly and symmetrically along both sides of the β‐sheet, but in basic glycinin, polarity on one side is fourfold that on the other throughout 70% of the protein. Polar residues distribute equally on either side of the β‐conglycinin subunit, but half of the acidic and basic residues concentrate in the N‐terminal third of the molecule. The remainder of the β‐conglycinin contains 90% of the molecule’s tyrosine, of which 70% is along one side. In the high‐proline protein, 90% of the tyrosine distributes to one side of a β‐sheet; 95% of the acidic residues to the other. Only soy oleosin approximates the per‐residue volume, polarity, and uniformity of silk or collagen. Its 85‐residue central lipophilic domain is much less polar than silk and nearly as uniform.