ASSIGNMENT OF THE BETA-SUBUNIT OF WHEAT EIF2 BY PROTEIN AND DNA-SEQUENCE ANALYSIS AND IMMUNOANALYSIS

Wheat germ initiation factor 2 (eIF2), like mammalian and yeast eIF2, contains three nonidentical subunits. The estimated molecular weights for the wheat subunits are 38,000 (p38), 42,000 (p42), and 50,000 (p50 ). Peptide sequence was obtained for the p38 subunit of wheat eIF2 and the resulting aminoacid sequence suggested that it was actually the e quivalent of the mammalian beta-subunit. A wheat sprout cDNA expressio n library was screened with antibody affinity purified to the p38 subu nit. The DNA sequence of the clones obtained also indicated that the p 38 subunit was the equivalent to the mammalian beta-subunit. The wheat p38 subunit was then expressed in Escherichia coli and antibodies rai sed to the purified recombinant protein. Only the p38 subunit of purif ied wheat germ eIF2 reacted with the antisera. The p38 subunit of whea t eIF2 is therefore the equivalent of mammalian eIF2 beta. (C) 1997 Ac ademic Press.