Polymorphism of legumin subunits from field bean (Vicia faba L. var. minor) and its relation to the corresponding multigene family

• Published in: Theoretical and applied genetics Vol. 86; no. 7; p. 867
• Main Authors: Horstmann, C, Schlesier, B, Otto, A, Kostka, S, Müntz, K
• Format: Journal Article
• Language: English
• Published: Germany 01.08.1993
• Subjects: adn; dna; gene; genes; genetic polymorphism; globulinas; globuline; globulins; polimorfismo genetico; polymorphisme genetique; vicia faba
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/BF00212614

Legumin, which amounts to approximately 55% of the seed protein in field beans (Vicia faba L. var. minor), is a representative of the 12S storage globulin family. The 12S storage globulins are hexameric holoprotein molecules composed of different types of polymorphic subunits encoded by a multigene family. 'Type-A' legumin subunits contain methionine whereas 'type-B' are methionine-free subunits. Sequencing of two different type A-specific cDNAs, as well as an FPLC/HPLC-based improvement of subunit fractionation and peptide mapping with subsequent partial amino-acid sequencing, permit the assignment of some of the polymorphic legumin subunits to members of the multigene family. Two different type A subunits (A1 and A2) correspond to the two different cDNA clones pVfLa129 (A2) and 165 (A1), but microheterogeneity in the amino-acid sequences indicates that polymorphic variants of both representatives of this type may exist. Two groups of published type B-specific gene sequences (LeB7, and LeB2, LeB4, LeB6, respectively) are represented by two polymorphic subunit fractions (B31, B311, and B41, B411). A seventh clone, LeB3, encodes one of the large legumin subunits that is only a minor component of the legumin seed protein complex.