Sequence analysis and comparison of cDNAs of the zein multigene family .

The nucleotide sequence of two zein cDNAs in hybrid plasmids A20 and B49 have been determined. The insert in A20 is 921 bp long including a 5' non-coding region of 60 nucleotides, preceded by what is believed to be an artifactual sequence of 41 nucleotides, and a 3' non-coding region of 87 nucleotides. The B49 insert is 467 bp long and includes approximately one-half the protein coding sequence as well as a 3' non-coding region of 97 nucleotides. These sequences have been compared with the previously published sequence of another zein clone, A30 . A20 and A30 , both encoding 19 000 mol. wt. zeins , have approximately 85% homology at the nucleotide level. The B49 sequence, corresponding to a 22 000 mol. wt. zein, has approximately 65% homology to either A20 or A30 . All three zeins share common features including nearly identical amino acid compositions. In addition, the tandem repeats of 20 amino acids first seen in A30 are also present in A20 and B49 .