Molecular Design of Soluble Zein Protein Sequences

Abstract

Zein is an insoluble prolamin protein extracted from corn that has various applications including organic coatings and encapsulation for candy, fruit, and pills. It is renewable, biodegradable and relatively inexpensive to produce. Incorporating a tunable solubility into zein presents many additional commercial and biomedical opportunities and may simplify processing of the material. In recent years, the sequence-based solubility prediction software made it possible to perform large scale predictions. In this work, we extract molecular design principles of soluble zein—based on the 22 kDa α-Zein sequence—by analyzing results that are consistent across different solubility predictors as well as those confirmed in experiment. The project is to be completed in three stages: 1) Generate potential soluble zein-based sequences by performing data mining and analysis through protein-solubility predictors (Protein-sol, ccSol, PROSO, PROSOII, SolPro). 2) Test predicted sequences through recombinant protein engineering techniques and structural characterization (e.g. X-ray crystallography). 3) Develop molecular models of soluble zeins based on outcomes of stage 2, to discover molecular mechanisms of solubility and extract molecular design principles. Stage 1, 2 and 3 are to be completed consecutively to develop a feedback loop for fast and effective protein design. At the current stage of the project, our goal is to generate potential soluble zein-based sequences by performing data mining and analysis through protein-solubility predictors (Protein-sol, ccSol, PROSO, PROSOII, SolPro). Our data reveal that the solubility changes tend to vary proportionally to the number of mutations introduced, as expected. We present several potentially soluble zein-based sequences.