SelProm: a queryable and predictive expression vector selection tool for Escherichia coli.

The rapid prototyping and optimizing of plasmid-based recombinant gene expression is one of the key steps in the development of bioengineered bacterial systems. Often, multiple genes or gene modules need to be co-expressed, and for this purpose compatible, inducible plasmid systems have been developed. However, inducible expression systems are not favored in industrial processes, due to their prohibitive cost, and consequently the conversion to constitutive expression systems is often desired. Here we present a set of constitutive-expression plasmids for this purpose, which were benchmarked using fluorescent reporter genes. To further facilitate the conversion between inducible and constitute expression systems, we developed SelProm, a design tool that serves as a parts repository of plasmid expression strength and predicts portability rules between constitutive and inducible plasmids through model comparison and machine learning. The SelProm tool is freely available at http://selprom.synbiochem.co.uk.