Disclosed are recombinant polypeptides that include human TRAIL sequences as well as human leucine zipper motifs as well as polynucleotides that encode the recombinant polypeptides, expression vectors that comprise the polynucleotides, pharmaceutical compositions comprising the polypeptides, and methods of using the pharmaceutical compositions for the treatment of cancer. Further disclosed are TRAIL sequences with stabilizing mutations and methods of expressing the disclosed polypeptides in E. coli.