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Thioredoxin activity in the C terminus of Phalaris S protein
Author(s) -
Li Xinmin,
Nield Jan,
Hayman David,
Langridge Peter
Publication year - 1995
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1995.08010133.x
Subject(s) - thioredoxin , ferredoxin thioredoxin reductase , dithiothreitol , biochemistry , thioredoxin reductase , gene , chemistry , homology (biology) , biology , enzyme
Self‐incompatibility in the grass Phalaris coerulescens is controlled by two genes S and Z . Isolation and sequencing of two S alleles showed that they encode proteins that are highly conserved at the C terminus with significant homology to thioredoxin H proteins. In particular, the residues in and around the active site of thioredoxin, Trp‐Cys‐Gly‐Pro‐Cys, are perfectly conserved. The C terminus of the S protein has been expressed in Eschericia coli and purified to homogeneity on Ni‐NTA resin. Functional assays showed that the protein has thioredoxin activity; it can act as a substrate for E. coli thioredoxin reductase and also catalyse the reduction of insulin by dithiothreitol. The possible role of thioredoxin‐like activity of the S protein in mediating the incompatibility reaction in Phalaris is discussed.